×

zbMATH — the first resource for mathematics

Shanno, David F.

Compute Distance To:
Author ID: shanno.david-f Recent zbMATH articles by "Shanno, David F."
Published as: Shanno, D. F.; Shanno, David; Shanno, David F.
External Links: MGP · Wikidata · GND
Documents Indexed: 66 Publications since 1970

Publications by Year

Citations contained in zbMATH

57 Publications have been cited 1,288 times in 895 Documents Cited by Year
Conditioning of quasi-Newton methods for function minimization. Zbl 0225.65073
Shanno, D. F.
176
1971
An interior-point algorithm for nonconvex nonlinear programming. Zbl 1040.90564
Vanderbei, Robert J.; Shanno, David F.
102
1999
Conjugate gradient methods with inexact searches. Zbl 0399.90077
Shanno, David F.
93
1978
Computational experience with a primal-dual interior point method for linear programming. Zbl 0731.65049
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
89
1991
On implementing Mehrotra’s predictor-corrector interior-point method for linear programming. Zbl 0771.90066
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
86
1992
Matrix conditioning and nonlinear optimization. Zbl 0371.90109
Shanno, D. F.; Phua, Kang-Hoh
79
1978
Interior point methods for linear programming: Computational state of the art. Zbl 0798.90100
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
60
1994
Minimization of unconstrained multivariate functions. Zbl 0319.65042
Shanno, D. F.; Phua, K. H.
56
1976
An implementation of a primal-dual interior point method for linear programming. Zbl 0752.90047
McShane, Kevin A.; Monma, Clyde L.; Shanno, David
51
1989
On the convergence of a new conjugate gradient algorithm. Zbl 0408.90071
Shanno, D. F.
51
1978
Interior-point methods for nonconvex nonlinear programming: Filter methods and merit functions. Zbl 1022.90017
Benson, Hande Y.; Vanderbei, Robert J.; Shanno, David F.
40
2002
Very large-scale linear programming: A case study in combining interior point and simplex methods. Zbl 0758.90056
Bixby, Robert E.; Gregory, John W.; Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
27
1992
An exact primal-dual penalty method approach to warmstarting interior-point methods for linear programming. Zbl 1171.90546
Benson, Hande Y.; Shanno, David F.
25
2007
Interior-point methods for nonconvex nonlinear programming: jamming and numerical testing. Zbl 1055.90068
Benson, Hande Y.; Shanno, David F.; Vanderbei, Robert J.
21
2004
Further development of a primal-dual interior point method. Zbl 0757.90051
Choi, In Chan; Monma, Clyde L.; Shanno, David F.
21
1990
Interior-point algorithms, penalty methods and equilibrium problems. Zbl 1121.90124
Benson, Hande Y.; Sen, Arun; Shanno, David F.; Vanderbei, Robert J.
19
2006
On variable-metric methods for sparse Hessians. Zbl 0424.65027
Shanno, D. F.
19
1980
Interior-point methods for nonconvex nonlinear programming: orderings and higher-order methods. Zbl 1054.90091
Shanno, David F.; Vanderbei, Robert J.
18
2000
Higher-order predictor-corrector interior point methods with application to quadratic objectives. Zbl 0794.90043
Carpenter, Tamra J.; Lustig, Irvin J.; Mulvey, John M.; Shanno, David F.
18
1993
Implementation of a dual affine interior point algorithm for linear programming. Zbl 0752.90046
Marsten, Roy E.; Saltzman, Matthew J.; Shanno, David F.; Pierce, George S.; Ballintijn, J. F.
17
1989
Computational experience with penalty-barrier methods for nonlinear programming. Zbl 0848.90108
Breitfeld, Marc G.; Shanno, David F.
15
1996
Interior-point methods for nonconvex nonlinear programming: Regularization and warmstarts. Zbl 1181.90243
Benson, Hande Y.; Shanno, David F.
14
2008
Computational experience with a globally convergent primal-dual predictor-corrector algorithm for linear programming. Zbl 0811.90068
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
13
1994
Computing Karmarkar projections quickly. Zbl 0652.90069
Shanno, David F.
13
1988
Parameter selection for modified Newton methods for function minimization. Zbl 0247.65041
Shanno, D. F.
13
1970
’Linear’ programming with absolute-value functionals. Zbl 0217.27201
Shanno, D. F.; Weil, R. L.
11
1971
Global convergence of a primal-dual interior-point method for nonlinear programming. Zbl 1277.90148
Griva, Igor; Shanno, David F.; Vanderbei, Robert J.; Benson, Hande Y.
9
2008
Preliminary computational experience with modified log-barrier functions for large-scale nonlinear programming. Zbl 0811.90093
Breitfeld, Marc G.; Shanno, David F.
9
1994
Numerical methods for robust regression: Linear models. Zbl 0615.65148
Shanno, David F.; Rocke, David M.
9
1986
Globally convergent conjugate gradient algorithms. Zbl 0579.90079
Shanno, David F.
9
1985
Numerical comparison of several variable metric algorithms. Zbl 0369.90124
Shanno, D. F.; Phua, K. H.
9
1978
Optimal conditioning of quasi-Newton methods. Zbl 0225.65074
Shanno, D. F.; Kettler, P. C.
9
1971
A comparative study of large-scale nonlinear optimization algorithms. Zbl 1066.90138
Benson, Hande Y.; Shanno, David F.; Vanderbei, Robert J.
8
2003
Interior-point methods for nonconvex nonlinear programming: cubic regularization. Zbl 1305.90333
Benson, Hande Y.; Shanno, David F.
7
2014
An infeasible-interior-point method for linear complementarity problems. Zbl 0913.65056
Simantiraki, Evangelia M.; Shanno, David F.
7
1997
Separable quadratic programming via a primal-dual interior point method and its use in a sequential procedure. Zbl 0777.90038
Carpenter, Tamra J.; Lustig, Irvin J.; Mulvey, John M.; Shanno, David F.
7
1993
The interaction of algorithms and architectures for interior point methods. Zbl 0814.90080
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
7
1992
The primal-dual interior point method on the Cray supercomputer. Zbl 0726.90055
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
7
1990
Conjugate gradient methods for linearly constrained nonlinear programming. Zbl 0477.90062
Shanno, D. F.; Marsten, R. E.
5
1982
An interior point method for quadratic programs based on conjugate projected gradients. Zbl 0778.90048
Carpenter, Tamra J.; Shanno, David F.
4
1993
A reduced-gradient variant of Karmarkar’s algorithm and null-space projections. Zbl 0621.90047
Shanno, D. F.; Marsten, R. E.
4
1988
An example of numerical nonconvergence of a variable-metric method. Zbl 0542.90082
Shanno, D. F.
4
1985
Interior point methods for linear and nonlinear programming. Zbl 0881.65052
Shanno, David F.; Simantiraki, Evangelia M.
3
1997
A unified view of interior point methods for linear programming. Zbl 0726.90049
Shanno, David F.; Bagchi, Ansuman
3
1990
An improved Marquardt procedure for nonlinear regressions. Zbl 0216.22402
Smith, F. B.; Shanno, D. F.
3
1971
An accelerated gradient projection method for linearly constrained nonlinear estimation. Zbl 0195.19803
Shanno, D. F.
3
1970
Optimization and dynamical systems algorithms for finding equilibria of stochastic games. Zbl 1154.91332
Sen, Arun; Shanno, David F.
2
2008
An infeasible-interior-point algorithm for solving mixed complementarity problems. Zbl 0886.90163
Simantiraki, Evangelia M.; Shanno, David F.
2
1997
The scale problem in robust regression M-estimates. Zbl 0642.62020
Rocke, David M.; Shanno, David F.
2
1986
Effective comparison of uncontrained optimization techniques. Zbl 0313.90055
Shanno, D. F.; Phua, K. H.
2
1975
Cubic regularization in symmetric rank-1 quasi-Newton methods. Zbl 1411.90315
Benson, Hande Y.; Shanno, David F.
1
2018
Who invented the interior-point method? Zbl 1270.90006
Shanno, David
1
2012
Computational methods for linear programming. Zbl 0829.90096
Shanno, D. F.
1
1994
The last word on interior point methods for linear programming - for now. Zbl 0800.90699
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
1
1994
Numerical experience with sequential quadratic programming algorithms for equality constrained nonlinear programming. Zbl 0677.65062
Shanno, David F.; Phua, Kang Hoh
1
1989
Adding variables to quasi-newton Hessian approximations. Zbl 0595.65071
Shanno, D. F.; Phua, K. H.
1
1987
Restarts and rotations of quasi-Newton methods. Zbl 0295.65045
Shanno, David F.; Berg, Allen; Cheston, Grant
1
1974
Cubic regularization in symmetric rank-1 quasi-Newton methods. Zbl 1411.90315
Benson, Hande Y.; Shanno, David F.
1
2018
Interior-point methods for nonconvex nonlinear programming: cubic regularization. Zbl 1305.90333
Benson, Hande Y.; Shanno, David F.
7
2014
Who invented the interior-point method? Zbl 1270.90006
Shanno, David
1
2012
Interior-point methods for nonconvex nonlinear programming: Regularization and warmstarts. Zbl 1181.90243
Benson, Hande Y.; Shanno, David F.
14
2008
Global convergence of a primal-dual interior-point method for nonlinear programming. Zbl 1277.90148
Griva, Igor; Shanno, David F.; Vanderbei, Robert J.; Benson, Hande Y.
9
2008
Optimization and dynamical systems algorithms for finding equilibria of stochastic games. Zbl 1154.91332
Sen, Arun; Shanno, David F.
2
2008
An exact primal-dual penalty method approach to warmstarting interior-point methods for linear programming. Zbl 1171.90546
Benson, Hande Y.; Shanno, David F.
25
2007
Interior-point algorithms, penalty methods and equilibrium problems. Zbl 1121.90124
Benson, Hande Y.; Sen, Arun; Shanno, David F.; Vanderbei, Robert J.
19
2006
Interior-point methods for nonconvex nonlinear programming: jamming and numerical testing. Zbl 1055.90068
Benson, Hande Y.; Shanno, David F.; Vanderbei, Robert J.
21
2004
A comparative study of large-scale nonlinear optimization algorithms. Zbl 1066.90138
Benson, Hande Y.; Shanno, David F.; Vanderbei, Robert J.
8
2003
Interior-point methods for nonconvex nonlinear programming: Filter methods and merit functions. Zbl 1022.90017
Benson, Hande Y.; Vanderbei, Robert J.; Shanno, David F.
40
2002
Interior-point methods for nonconvex nonlinear programming: orderings and higher-order methods. Zbl 1054.90091
Shanno, David F.; Vanderbei, Robert J.
18
2000
An interior-point algorithm for nonconvex nonlinear programming. Zbl 1040.90564
Vanderbei, Robert J.; Shanno, David F.
102
1999
An infeasible-interior-point method for linear complementarity problems. Zbl 0913.65056
Simantiraki, Evangelia M.; Shanno, David F.
7
1997
Interior point methods for linear and nonlinear programming. Zbl 0881.65052
Shanno, David F.; Simantiraki, Evangelia M.
3
1997
An infeasible-interior-point algorithm for solving mixed complementarity problems. Zbl 0886.90163
Simantiraki, Evangelia M.; Shanno, David F.
2
1997
Computational experience with penalty-barrier methods for nonlinear programming. Zbl 0848.90108
Breitfeld, Marc G.; Shanno, David F.
15
1996
Interior point methods for linear programming: Computational state of the art. Zbl 0798.90100
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
60
1994
Computational experience with a globally convergent primal-dual predictor-corrector algorithm for linear programming. Zbl 0811.90068
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
13
1994
Preliminary computational experience with modified log-barrier functions for large-scale nonlinear programming. Zbl 0811.90093
Breitfeld, Marc G.; Shanno, David F.
9
1994
Computational methods for linear programming. Zbl 0829.90096
Shanno, D. F.
1
1994
The last word on interior point methods for linear programming - for now. Zbl 0800.90699
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
1
1994
Higher-order predictor-corrector interior point methods with application to quadratic objectives. Zbl 0794.90043
Carpenter, Tamra J.; Lustig, Irvin J.; Mulvey, John M.; Shanno, David F.
18
1993
Separable quadratic programming via a primal-dual interior point method and its use in a sequential procedure. Zbl 0777.90038
Carpenter, Tamra J.; Lustig, Irvin J.; Mulvey, John M.; Shanno, David F.
7
1993
An interior point method for quadratic programs based on conjugate projected gradients. Zbl 0778.90048
Carpenter, Tamra J.; Shanno, David F.
4
1993
On implementing Mehrotra’s predictor-corrector interior-point method for linear programming. Zbl 0771.90066
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
86
1992
Very large-scale linear programming: A case study in combining interior point and simplex methods. Zbl 0758.90056
Bixby, Robert E.; Gregory, John W.; Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
27
1992
The interaction of algorithms and architectures for interior point methods. Zbl 0814.90080
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
7
1992
Computational experience with a primal-dual interior point method for linear programming. Zbl 0731.65049
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
89
1991
Further development of a primal-dual interior point method. Zbl 0757.90051
Choi, In Chan; Monma, Clyde L.; Shanno, David F.
21
1990
The primal-dual interior point method on the Cray supercomputer. Zbl 0726.90055
Lustig, Irvin J.; Marsten, Roy E.; Shanno, David F.
7
1990
A unified view of interior point methods for linear programming. Zbl 0726.90049
Shanno, David F.; Bagchi, Ansuman
3
1990
An implementation of a primal-dual interior point method for linear programming. Zbl 0752.90047
McShane, Kevin A.; Monma, Clyde L.; Shanno, David
51
1989
Implementation of a dual affine interior point algorithm for linear programming. Zbl 0752.90046
Marsten, Roy E.; Saltzman, Matthew J.; Shanno, David F.; Pierce, George S.; Ballintijn, J. F.
17
1989
Numerical experience with sequential quadratic programming algorithms for equality constrained nonlinear programming. Zbl 0677.65062
Shanno, David F.; Phua, Kang Hoh
1
1989
Computing Karmarkar projections quickly. Zbl 0652.90069
Shanno, David F.
13
1988
A reduced-gradient variant of Karmarkar’s algorithm and null-space projections. Zbl 0621.90047
Shanno, D. F.; Marsten, R. E.
4
1988
Adding variables to quasi-newton Hessian approximations. Zbl 0595.65071
Shanno, D. F.; Phua, K. H.
1
1987
Numerical methods for robust regression: Linear models. Zbl 0615.65148
Shanno, David F.; Rocke, David M.
9
1986
The scale problem in robust regression M-estimates. Zbl 0642.62020
Rocke, David M.; Shanno, David F.
2
1986
Globally convergent conjugate gradient algorithms. Zbl 0579.90079
Shanno, David F.
9
1985
An example of numerical nonconvergence of a variable-metric method. Zbl 0542.90082
Shanno, D. F.
4
1985
Conjugate gradient methods for linearly constrained nonlinear programming. Zbl 0477.90062
Shanno, D. F.; Marsten, R. E.
5
1982
On variable-metric methods for sparse Hessians. Zbl 0424.65027
Shanno, D. F.
19
1980
Conjugate gradient methods with inexact searches. Zbl 0399.90077
Shanno, David F.
93
1978
Matrix conditioning and nonlinear optimization. Zbl 0371.90109
Shanno, D. F.; Phua, Kang-Hoh
79
1978
On the convergence of a new conjugate gradient algorithm. Zbl 0408.90071
Shanno, D. F.
51
1978
Numerical comparison of several variable metric algorithms. Zbl 0369.90124
Shanno, D. F.; Phua, K. H.
9
1978
Minimization of unconstrained multivariate functions. Zbl 0319.65042
Shanno, D. F.; Phua, K. H.
56
1976
Effective comparison of uncontrained optimization techniques. Zbl 0313.90055
Shanno, D. F.; Phua, K. H.
2
1975
Restarts and rotations of quasi-Newton methods. Zbl 0295.65045
Shanno, David F.; Berg, Allen; Cheston, Grant
1
1974
Conditioning of quasi-Newton methods for function minimization. Zbl 0225.65073
Shanno, D. F.
176
1971
’Linear’ programming with absolute-value functionals. Zbl 0217.27201
Shanno, D. F.; Weil, R. L.
11
1971
Optimal conditioning of quasi-Newton methods. Zbl 0225.65074
Shanno, D. F.; Kettler, P. C.
9
1971
An improved Marquardt procedure for nonlinear regressions. Zbl 0216.22402
Smith, F. B.; Shanno, D. F.
3
1971
Parameter selection for modified Newton methods for function minimization. Zbl 0247.65041
Shanno, D. F.
13
1970
An accelerated gradient projection method for linearly constrained nonlinear estimation. Zbl 0195.19803
Shanno, D. F.
3
1970
all top 5

Cited by 1,288 Authors

26 Andrei, Neculai
19 Shanno, David F.
17 Gondzio, Jacek
14 Ford, John A.
14 Ye, Yinyu
13 Lukšan, Ladislav
12 Nocedal, Jorge
11 Júdice, Joaquim João
11 Mészáros, Csaba
10 Babaie-Kafaki, Saman
9 Goldfarb, Donald
9 Mizuno, Shinji
9 Oliveira, Aurelio Ribeiro Leite
9 Terlaky, Tamás
9 Toint, Philippe L.
9 Zhang, Yin
8 Martínez, José Mario
8 Todd, Michael J.
7 Al-Baali, Mehiddin
7 Armand, Paul
7 Fernandes, Edite M. G. P.
7 Leong, Wah June
7 Moghrabi, Issam A. R.
7 Orban, Dominique
7 Polyak, Roman A.
7 Roos, Cornelis
7 Shi, Zhenjun
7 Spedicato, Emilio
7 Vanderbei, Robert Joseph
6 Benson, Hande Y.
6 Dai, Yu-Hong
6 Hassan, Malik Abu
6 Mahdavi-Amiri, Nezam
6 Mitchell, John E.
6 Storey, Colin
6 Tapia, Richard A.
5 Curtis, Frank E.
5 González-Lima, María D.
5 Jarre, Florian
5 Kojima, Masakazu
5 Leyffer, Sven
5 Lucidi, Stefano
5 Lustig, Irvin J.
5 Rustem, Berc
5 Vlček, Jan
4 Andreani, Roberto
4 Anstreicher, Kurt M.
4 Arbel, Ami
4 Benoist, Joël
4 Byrd, Richard H.
4 Costa, M. Fernanda P.
4 Ekblom, Håkan
4 Escudero, Laureano Fernando
4 Ghanbari, Reza
4 Gilbert, Jean Charles
4 Griva, Igor A.
4 Ingber, Lester
4 Jansen, Benjamin
4 Kanno, Yoshihiro
4 Kimiaei, Morteza
4 Kočvara, Michal
4 Liu, Hongwei
4 Liu, Xinwei
4 Matonoha, Ctirad
4 Oren, Shmuel S.
4 Ou, Yigui
4 Pintelas, Panagiotis E.
4 Portugal, Luis F.
4 Pu, Dingguo
4 Ruggiero, Valeria
4 Saadallah, Adel F.
4 Santos, Sandra Augusta
4 Sellami, Badreddine
4 Shen, Jie
4 Tsuchiya, Takashi
3 Amini, Keyvan
3 Biegler, Lorenz T.
3 Biglari, Fahimeh
3 Boggs, Paul T.
3 Bonettini, Silvia
3 Borzì, Alfio
3 Caboussat, Alexandre
3 Chaib, Yacine
3 D’Apuzzo, Marco
3 Dixon, Laurence C. W.
3 Engau, Alexander
3 Faramarzi, Parvaneh
3 Guest, James K.
3 Liu, Hao
3 Liuzzi, Giampaolo
3 Livieris, Ioannis E.
3 Mehrotra, Sanjay
3 Mitra, Gautam
3 Mulvey, John M.
3 Omheni, Riadh
3 Pardalos, Panos M.
3 Phua, Kang-Hoh
3 Potra, Florian-Alexandru
3 Resende, Mauricio G. C.
3 Schnabel, Robert B.
...and 1,188 more Authors
all top 5

Cited in 164 Serials

86 Mathematical Programming. Series A. Series B
68 Journal of Optimization Theory and Applications
57 Computational Optimization and Applications
57 Optimization Methods & Software
44 Journal of Computational and Applied Mathematics
38 European Journal of Operational Research
29 Optimization
27 Annals of Operations Research
25 Mathematical Programming
23 Computers & Operations Research
21 Applied Mathematics and Computation
17 Numerical Algorithms
16 Computers & Mathematics with Applications
14 Computer Methods in Applied Mechanics and Engineering
13 Optimization Letters
12 Mathematics of Computation
11 Operations Research Letters
11 Linear Algebra and its Applications
9 Optimization and Engineering
9 Journal of Industrial and Management Optimization
8 Applied Mathematics Letters
8 International Journal of Computer Mathematics
8 Computational Statistics and Data Analysis
7 International Journal for Numerical Methods in Engineering
7 Mathematical Methods of Operations Research
7 Mathematical Programming Computation
6 Calcolo
6 Computing
6 Numerische Mathematik
6 Applied Numerical Mathematics
6 Mathematical and Computer Modelling
6 Applied Mathematical Modelling
6 Top
5 Journal of Computational Physics
5 Kybernetika
5 Computational and Applied Mathematics
4 Automatica
4 BIT
4 SIAM Journal on Optimization
4 Mathematical Problems in Engineering
4 RAIRO. Operations Research
4 Journal of Applied Mathematics and Computing
3 Journal of the Franklin Institute
3 Algorithmica
3 Journal of Global Optimization
3 Computational Statistics
3 SIAM Journal on Scientific Computing
3 Applied Mathematics. Series B (English Edition)
3 Parallel Algorithms and Applications
3 European Journal of Mechanics. A. Solids
3 International Journal of Applied Mathematics and Computer Science
3 Statistics and Computing
2 Journal of Fluid Mechanics
2 Journal of Mathematical Analysis and Applications
2 Psychometrika
2 Applied Mathematics and Optimization
2 Biometrics
2 Journal of Soviet Mathematics
2 Networks
2 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods
2 Computer Aided Geometric Design
2 RAIRO. Modélisation Mathématique et Analyse Numérique
2 Acta Mathematicae Applicatae Sinica. English Series
2 Computational Mechanics
2 Journal of Economic Dynamics & Control
2 Communications in Statistics. Simulation and Computation
2 Journal of Statistical Computation and Simulation
2 SIAM Review
2 Numerical Linear Algebra with Applications
2 Engineering Analysis with Boundary Elements
2 International Transactions in Operational Research
2 INFORMS Journal on Computing
2 Abstract and Applied Analysis
2 Soft Computing
2 Wuhan University Journal of Natural Sciences (WUJNS)
2 Archives of Computational Methods in Engineering
2 Journal of Machine Learning Research (JMLR)
2 SIAM Journal on Applied Dynamical Systems
2 Structural and Multidisciplinary Optimization
2 4OR
2 Computational Management Science
2 Pesquisa Operacional
2 EURO Journal on Computational Optimization
2 Journal of Mathematical Modeling
1 The Canadian Journal of Statistics
1 Computers and Fluids
1 Computer Physics Communications
1 International Journal of Control
1 International Journal of Mathematical Education in Science and Technology
1 International Journal for Numerical Methods in Fluids
1 Information Processing Letters
1 Periodica Mathematica Hungarica
1 Molecular Simulation
1 Acta Mathematica Vietnamica
1 Aplikace Matematiky
1 Fuzzy Sets and Systems
1 International Journal of Mathematics and Mathematical Sciences
1 Journal of the American Statistical Association
1 Journal of Econometrics
1 Journal of Mathematical Psychology
...and 64 more Serials

Citations by Year

Wikidata Timeline

The data are displayed as stored in Wikidata under a Creative Commons CC0 License. Updates and corrections should be made in Wikidata.