Tag: matrix

558 How to define a two-dimensional array in Python 2011-07-12T15:54:38.027

397 Transpose/Unzip Function (inverse of zip)? 2008-08-21T04:29:07.580

315 How can I index a MATLAB array returned by a function without first assigning it to a local variable? 2010-09-02T12:34:36.773

281 How do you rotate a two dimensional array? 2008-09-03T20:34:33.783

278 What are the differences between numpy arrays and matrices? Which one should I use? 2010-11-11T03:25:09.680

216 What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and benefit tradeoffs? 2009-09-04T16:45:58.510

212 Bomb dropping algorithm 2013-03-08T17:47:03.497

210 Difference between numpy.array shape (R, 1) and (R,) 2014-02-26T20:55:35.657

143 Performance of Java matrix math libraries? 2009-02-09T19:12:03.783

140 Should I use a data.frame or a matrix? 2011-03-01T18:36:16.523

137 Looping in a spiral 2008-12-29T18:40:29.320

124 how does multiplication differ for NumPy Matrix vs Array classes? 2010-10-08T12:50:47.820

117 Numpy matrix to array 2010-07-26T17:25:23.203

115 numpy matrix vector multiplication 2014-02-04T20:43:59.887

113 Finding row index containing maximum value using R 2009-04-13T11:13:51.627

112 R memory management / cannot allocate vector of size n Mb 2011-03-02T18:13:01.340

112 Select rows of a matrix that meet a condition 2011-03-22T12:21:48.457

109 Reshape three column data frame to matrix ("long" to "wide" format) 2012-03-08T12:03:00.553

101 Transposing a 2D-array in JavaScript 2013-07-02T14:43:06.480

98 Apply a function to every row of a matrix or a data frame 2010-11-21T03:59:59.417

98 How do I find the length (or dimensions, size) of a numpy matrix in python? 2013-02-13T06:07:24.577

94 How can I apply a function to every row/column of a matrix in MATLAB? 2010-02-21T19:58:27.290

92 How do I make a matrix from a list of vectors in R? 2009-08-25T18:02:36.033

86 Why are quaternions used for rotations? 2012-01-18T23:30:36.620

82 Android: How to rotate a bitmap on a center point 2010-11-12T16:38:32.243

79 Convert a matrix to a 1 dimensional array 2010-09-29T15:38:56.670

77 Very large matrices using Python and NumPy 2009-06-28T00:32:21.983

77 How can I create a correlation matrix in R? 2012-05-21T06:53:09.933

74 How do I iterate through each element in an n-dimensional matrix in MATLAB? 2009-04-17T02:12:19.317

74 Join tiles in Corona SDK into one word for a Breakout game grid? 2016-07-20T14:44:01.797

68 How can I count the number of elements of a given value in a matrix? 2010-05-21T09:29:49.763

66 inverting a 4x4 matrix 2009-07-18T19:04:34.033

66 Function for 'does matrix contain value X?' 2009-12-16T10:15:47.477

66 Recommendation for C# Matrix Library 2010-02-25T18:46:49.330

65 Find the row representing the smallest integer in row wise sorted matrix 2010-11-29T12:45:18.880

63 How to use onSensorChanged sensor data in combination with OpenGL 2010-05-21T10:02:48.213

63 How to subset matrix to one column, maintain matrix data type, maintain row/column names? 2011-09-08T17:39:10.913

63 Convert a 1D array to a 2D array in numpy 2012-09-25T02:23:30.423

61 Multiply rows of matrix by vector? 2010-09-04T18:51:20.713

61 How to convert a matrix to a list of column-vectors in R? 2011-07-25T17:08:08.570

60 Numpy ‘smart’ symmetric matrix 2010-04-03T22:39:56.293

60 Elegant indexing up to end of vector/matrix 2011-09-21T13:33:21.953

59 In WebGL what are the differences between an attribute, a uniform, and a varying variable? 2013-07-09T00:01:44.803

59 Confusion between C++ and OpenGL matrix order (row-major vs column-major) 2013-07-18T07:46:54.017

58 Split a large dataframe into a list of data frames based on common value in column 2013-08-30T07:14:29.190

57 data type not understood 2011-03-27T01:10:10.913

55 Python Inverse of a Matrix 2008-10-17T05:30:49.997

55 All Levels of a Factor in a Model Matrix in R 2010-12-30T06:18:17.157

54 Looking for an explanation of post/pre/set Translate (in Matrix object) and how to use them 2011-11-19T21:56:41.920

53 Sum a list of matrices 2012-07-25T02:05:07.543

52 How to convert a huge list-of-vector to a matrix more efficiently in R? 2012-11-05T00:40:34.230

51 How to create an empty matrix in R? 2014-02-05T18:40:16.703

50 undefined reference to `std::ios_base::Init::Init()' 2012-06-05T23:15:12.297

50 How to divide each row of a matrix by elements of a vector in R 2013-12-15T15:55:26.357

49 Get the indices of the n largest elements in a matrix 2010-04-22T16:05:26.330

49 Generate a matrix containing all combinations of elements taken from n vectors 2014-02-20T00:02:10.400

48 What techniques exists in R to visualize a "distance matrix"? 2010-06-20T21:49:53.513

48 How to turn a vector into a matrix in R? 2013-01-30T22:19:48.137

48 Find row and column index of maximum value in a matrix 2013-07-12T03:10:28.933

48 Counting the number of non-NaN elements in a numpy ndarray matrix in Python 2014-02-14T11:26:25.620

47 How do I visualize a matrix with colors and values displayed? 2010-10-15T13:57:31.393

46 How to apply function over each matrix element's indices 2011-09-12T23:58:12.113

46 Remove a column from a matrix in GNU Octave 2012-09-12T14:25:55.420

45 How can I sort a 2-D array in MATLAB with respect to one column? 2008-09-25T17:30:02.143

45 difference between numpy dot() and inner() 2012-06-14T12:59:21.730

45 Rotate a Matrix in R 2013-05-11T10:37:04.233

44 Android: Matrix -> what is the different between preconcat and postconcat? 2010-10-04T13:18:09.880

44 How to get element-wise matrix multiplication (Hadamard product) in numpy? 2016-10-14T04:35:47.350

43 Scipy sparse... arrays? 2010-03-29T17:48:57.100

42 Pretty print 2D Python list 2012-11-04T00:12:56.030

42 Why is the diag function so slow? [in R 3.2.0 or earlier] 2015-05-04T17:13:12.143

41 Get all the diagonals in a matrix/list of lists in Python 2011-06-11T00:38:53.087

41 Matrix Multiplication in Clojure vs Numpy 2012-01-17T18:31:01.420

41 Appending a list to a list of lists in R 2013-02-13T07:03:30.577

41 Right way to convert data.frame to a numeric matrix, when df also contains strings? 2013-05-13T09:10:59.857

40 How to rotate a table 45 degrees and save the result into another table? 2011-02-26T11:23:52.470

40 numpy get index where value is true 2013-04-18T23:05:51.980

39 Dynamic programming - Largest square block 2009-11-13T01:46:30.003

39 Concatenating Matrices in R 2011-09-06T19:06:07.393

39 Convert Eigen Matrix to C array 2011-12-09T08:53:35.573

38 Subscript out of bounds - general definition and solution? 2013-02-22T19:00:48.557

38 Create dataframe from a matrix 2013-04-08T17:17:25.853

37 How to make List from Numpy Matrix in Python 2011-03-03T16:26:49.210

37 Vector of Vectors to create matrix 2012-09-11T18:18:05.037

37 Flattening SVG matrix transforms in Inkscape 2013-02-04T10:31:58.390

36 What does a circled plus mean? 2009-05-08T11:58:20.100

36 Matrix from Python to MATLAB 2009-07-07T22:55:08.403

36 Calculate Matrix Rank using scipy 2010-03-18T23:10:19.367

36 whats the fastest way to find eigenvalues/vectors in python? 2011-07-13T19:08:06.810

36 How to map the indexes of a matrix to a 1-dimensional array (C++)? 2012-12-23T23:35:39.893

36 Scale and mirror SVG object 2014-05-27T22:03:17.417

36 numpy subtract every row of matrix by vector 2014-10-13T04:43:36.747

36 Why does m[1] - m[0] return 3 where m is a 3x3 matrix? 2016-03-07T12:53:46.723

35 Extract matrix column values by matrix column name 2011-04-21T13:20:52.177

35 Google Distance Matrix API Alternatives? 2011-05-28T17:10:57.630

35 Selecting only a specific number of rows fulfilling a condition 2011-11-13T13:28:53.247

35 Deprecation status of the NumPy matrix class 2018-11-12T00:49:55.197

34 Array of Matrices in MATLAB 2009-01-21T20:59:54.537

34 Simple 3x3 matrix inverse code (C++) 2009-06-11T22:06:27.200