colt

Java Hash Multi Map (key with multiple values) Implementation

由 前提是你 提交于 2020-01-01 16:56:52
问题 From here, I found that Colt's OpenIntIntHashMap and Trove's TIntIntHashMap give better performance and memory uses than Java's built in HashMap or Guava's HashMultimap . Do Colt's OpenIntIntHashMap or Trove's TIntIntHashMap allow keys with multiple values, as with HashMultimap ? If not what is a nice way to implement a HashMultimap that can achieve Colt's or Trove's performance and memory efficiency? Note: I have tested Guava's HashMultimap , but its performance and memory efficiency seems

Cholesky decomposition of large sparse matrices in Java

由 笑着哭i 提交于 2019-12-24 15:27:24
问题 I want to do Cholesky decomposition of large sparse matrices in Java. Currently I'm using the Parallel Colt library class SparseDoubleCholeskyDecomposition but it's much slower than using my code I wrote in C for dense matrices which I use in java with JNI. For example for 5570x5570 matrices with a non-zero density of 0.25% with SparseDoubleCholeskyDecomposition takes 26.6 seconds to factor and my own code for the same matrix using dense storage only takes 1.12 seconds . However, if I set the

How to iterate over non zero values in a sparse matrix with COLT?

由 走远了吗. 提交于 2019-12-24 12:08:18
问题 The code example on the COLT website shows: DoubleFactory2D factory; factory = DoubleFactory2D.sparse; DoubleMatrix2D matrix = factory.make(3,4); for (int row = matrix.rows(); --row >= 0;) { for (int column = matrix.columns(); --column >= 0;) { value = matrix.getQuick(row, column); } } but this does not take advantage of the sparsity of the matrix. I'd like to iterate over non zero values only. 来源： https://stackoverflow.com/questions/44655457/how-to-iterate-over-non-zero-values-in-a-sparse

Singular Value Decomposition: Different results with Jama, PColt and NumPy

由 风格不统一 提交于 2019-12-11 08:36:51
问题 I want to perform Singular Value Decomposition on a large (sparse) matrix. In order to choose the best(most accurate) library, I tried replicating the SVD example provided here using different Java and Python libraries. Strangely I am getting different results with each library. Here's the original example matrix and it's decomposed (U S and VT) matrices: A =2.0 0.0 8.0 6.0 0.0 1.0 6.0 0.0 1.0 7.0 5.0 0.0 7.0 4.0 0.0 7.0 0.0 8.0 5.0 0.0 0.0 10.0 0.0 0.0 7.0 U =-0.54 0.07 0.82 -0.11 0.12 -0.10

'matrix too large' exception using colt java lib

由 。_饼干妹妹 提交于 2019-12-10 21:27:27
问题 I was using cern.colt.matrix.* lib for sparse matrix calculations ..but it seems that I keep running into this error: Exception in thread "main" java.lang.IllegalArgumentException: matrix too large I think this is because the constructor throws exception when nrows*ncols > INTEGER.max api: http://acs.lbl.gov/software/colt/api/cern/colt/matrix/impl/SparseDoubleMatrix2D.html exception: IllegalArgumentException - if rows<0 || columns<0 || (double)columns*rows > Integer.MAX_VALUE. My rows are:

Is there a way to find common elements in multiple lists?

由 ∥☆過路亽．° 提交于 2019-12-04 18:05:32
问题 I have a list of integer arrays. I need to find the common elements between those. What I can think of is an extension of what is listed in Common elements in two lists Example would be [1,3,5], [1,6,7,9,3], [1,3,10,11] should result in [1,3] There are no duplicates in the arrays as well. Is there a straight forward way to do this? 回答1: You can transform the lists to sets, and then use Set.retainAll method for intersection between the different sets. Once you intersect all sets, you are left

Java Hash Multi Map (key with multiple values) Implementation

由 强颜欢笑 提交于 2019-12-04 12:26:00
From here , I found that Colt's OpenIntIntHashMap and Trove's TIntIntHashMap give better performance and memory uses than Java's built in HashMap or Guava's HashMultimap . Do Colt's OpenIntIntHashMap or Trove's TIntIntHashMap allow keys with multiple values, as with HashMultimap ? If not what is a nice way to implement a HashMultimap that can achieve Colt's or Trove's performance and memory efficiency? Note: I have tested Guava's HashMultimap , but its performance and memory efficiency seems poor to me. Multimaps.newSetMultimap( TDecorators.wrap(new TIntObjectHashMap<Collection<Integer>>()),

Java matrix libraries

由 六眼飞鱼酱① 提交于 2019-11-26 22:11:20
I was wondering whether any of the well-known matrix libraries for Java, such as Colt or EJML, actually provide similar functionality as MatLab? For instance, I can't seem to find anywhere in the definition of their API simple method to add or subtract two matrices/vectors by each other, which seems to be the most common operation used. Am I missing something? Try Apache Commons Math library. org.apache.commons.math3.linear package contains the functions that you want. Home page Christian Fries Some Java libraries for linear algebra are: Apache Commons Math: http://commons.apache.org/proper

Java matrix libraries

由 ε祈祈猫儿з 提交于 2019-11-26 09:08:40
问题 I was wondering whether any of the well-known matrix libraries for Java, such as Colt or EJML, actually provide similar functionality as MatLab? For instance, I can\'t seem to find anywhere in the definition of their API simple method to add or subtract two matrices/vectors by each other, which seems to be the most common operation used. Am I missing something? 回答1: Try Apache Commons Math library. org.apache.commons.math3.linear package contains the functions that you want. Home page 回答2:
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