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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2009 Gael Guennebaud <gael.guennebaud (at) inria.fr>
      5 //
      6 // This Source Code Form is subject to the terms of the Mozilla
      7 // Public License v. 2.0. If a copy of the MPL was not distributed
      8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
      9 
     10 #include "main.h"
     11 
     12 // workaround aggressive optimization in ICC
     13 template<typename T> EIGEN_DONT_INLINE  T sub(T a, T b) { return a - b; }
     14 
     15 template<typename T> bool isFinite(const T& x)
     16 {
     17   return isNotNaN(sub(x,x));
     18 }
     19 
     20 template<typename T> EIGEN_DONT_INLINE T copy(const T& x)
     21 {
     22   return x;
     23 }
     24 
     25 template<typename MatrixType> void stable_norm(const MatrixType& m)
     26 {
     27   /* this test covers the following files:
     28      StableNorm.h
     29   */
     30   using std::sqrt;
     31   using std::abs;
     32   typedef typename MatrixType::Index Index;
     33   typedef typename MatrixType::Scalar Scalar;
     34   typedef typename NumTraits<Scalar>::Real RealScalar;
     35 
     36   // Check the basic machine-dependent constants.
     37   {
     38     int ibeta, it, iemin, iemax;
     39 
     40     ibeta = std::numeric_limits<RealScalar>::radix;         // base for floating-point numbers
     41     it    = std::numeric_limits<RealScalar>::digits;        // number of base-beta digits in mantissa
     42     iemin = std::numeric_limits<RealScalar>::min_exponent;  // minimum exponent
     43     iemax = std::numeric_limits<RealScalar>::max_exponent;  // maximum exponent
     44 
     45     VERIFY( (!(iemin > 1 - 2*it || 1+it>iemax || (it==2 && ibeta<5) || (it<=4 && ibeta <= 3 ) || it<2))
     46            && "the stable norm algorithm cannot be guaranteed on this computer");
     47   }
     48 
     49 
     50   Index rows = m.rows();
     51   Index cols = m.cols();
     52 
     53   // get a non-zero random factor
     54   Scalar factor = internal::random<Scalar>();
     55   while(numext::abs2(factor)<RealScalar(1e-4))
     56     factor = internal::random<Scalar>();
     57   Scalar big = factor * ((std::numeric_limits<RealScalar>::max)() * RealScalar(1e-4));
     58 
     59   factor = internal::random<Scalar>();
     60   while(numext::abs2(factor)<RealScalar(1e-4))
     61     factor = internal::random<Scalar>();
     62   Scalar small = factor * ((std::numeric_limits<RealScalar>::min)() * RealScalar(1e4));
     63 
     64   MatrixType  vzero = MatrixType::Zero(rows, cols),
     65               vrand = MatrixType::Random(rows, cols),
     66               vbig(rows, cols),
     67               vsmall(rows,cols);
     68 
     69   vbig.fill(big);
     70   vsmall.fill(small);
     71 
     72   VERIFY_IS_MUCH_SMALLER_THAN(vzero.norm(), static_cast<RealScalar>(1));
     73   VERIFY_IS_APPROX(vrand.stableNorm(),      vrand.norm());
     74   VERIFY_IS_APPROX(vrand.blueNorm(),        vrand.norm());
     75   VERIFY_IS_APPROX(vrand.hypotNorm(),       vrand.norm());
     76 
     77   RealScalar size = static_cast<RealScalar>(m.size());
     78 
     79   // test isFinite
     80   VERIFY(!isFinite( std::numeric_limits<RealScalar>::infinity()));
     81   VERIFY(!isFinite(sqrt(-abs(big))));
     82 
     83   // test overflow
     84   VERIFY(isFinite(sqrt(size)*abs(big)));
     85   VERIFY_IS_NOT_APPROX(sqrt(copy(vbig.squaredNorm())), abs(sqrt(size)*big)); // here the default norm must fail
     86   VERIFY_IS_APPROX(vbig.stableNorm(), sqrt(size)*abs(big));
     87   VERIFY_IS_APPROX(vbig.blueNorm(),   sqrt(size)*abs(big));
     88   VERIFY_IS_APPROX(vbig.hypotNorm(),  sqrt(size)*abs(big));
     89 
     90   // test underflow
     91   VERIFY(isFinite(sqrt(size)*abs(small)));
     92   VERIFY_IS_NOT_APPROX(sqrt(copy(vsmall.squaredNorm())),   abs(sqrt(size)*small)); // here the default norm must fail
     93   VERIFY_IS_APPROX(vsmall.stableNorm(), sqrt(size)*abs(small));
     94   VERIFY_IS_APPROX(vsmall.blueNorm(),   sqrt(size)*abs(small));
     95   VERIFY_IS_APPROX(vsmall.hypotNorm(),  sqrt(size)*abs(small));
     96 
     97   // Test compilation of cwise() version
     98   VERIFY_IS_APPROX(vrand.colwise().stableNorm(),      vrand.colwise().norm());
     99   VERIFY_IS_APPROX(vrand.colwise().blueNorm(),        vrand.colwise().norm());
    100   VERIFY_IS_APPROX(vrand.colwise().hypotNorm(),       vrand.colwise().norm());
    101   VERIFY_IS_APPROX(vrand.rowwise().stableNorm(),      vrand.rowwise().norm());
    102   VERIFY_IS_APPROX(vrand.rowwise().blueNorm(),        vrand.rowwise().norm());
    103   VERIFY_IS_APPROX(vrand.rowwise().hypotNorm(),       vrand.rowwise().norm());
    104 }
    105 
    106 void test_stable_norm()
    107 {
    108   for(int i = 0; i < g_repeat; i++) {
    109     CALL_SUBTEST_1( stable_norm(Matrix<float, 1, 1>()) );
    110     CALL_SUBTEST_2( stable_norm(Vector4d()) );
    111     CALL_SUBTEST_3( stable_norm(VectorXd(internal::random<int>(10,2000))) );
    112     CALL_SUBTEST_4( stable_norm(VectorXf(internal::random<int>(10,2000))) );
    113     CALL_SUBTEST_5( stable_norm(VectorXcd(internal::random<int>(10,2000))) );
    114   }
    115 }
    116