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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2009-2014 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 template<typename T> EIGEN_DONT_INLINE T copy(const T& x)
     13 {
     14   return x;
     15 }
     16 
     17 template<typename MatrixType> void stable_norm(const MatrixType& m)
     18 {
     19   /* this test covers the following files:
     20      StableNorm.h
     21   */
     22   using std::sqrt;
     23   using std::abs;
     24   typedef typename MatrixType::Index Index;
     25   typedef typename MatrixType::Scalar Scalar;
     26   typedef typename NumTraits<Scalar>::Real RealScalar;
     27 
     28   bool complex_real_product_ok = true;
     29 
     30   // Check the basic machine-dependent constants.
     31   {
     32     int ibeta, it, iemin, iemax;
     33 
     34     ibeta = std::numeric_limits<RealScalar>::radix;         // base for floating-point numbers
     35     it    = std::numeric_limits<RealScalar>::digits;        // number of base-beta digits in mantissa
     36     iemin = std::numeric_limits<RealScalar>::min_exponent;  // minimum exponent
     37     iemax = std::numeric_limits<RealScalar>::max_exponent;  // maximum exponent
     38 
     39     VERIFY( (!(iemin > 1 - 2*it || 1+it>iemax || (it==2 && ibeta<5) || (it<=4 && ibeta <= 3 ) || it<2))
     40            && "the stable norm algorithm cannot be guaranteed on this computer");
     41 
     42     Scalar inf = std::numeric_limits<RealScalar>::infinity();
     43     if(NumTraits<Scalar>::IsComplex && (numext::isnan)(inf*RealScalar(1)) )
     44     {
     45       complex_real_product_ok = false;
     46       static bool first = true;
     47       if(first)
     48         std::cerr << "WARNING: compiler mess up complex*real product, " << inf << " * " << 1.0 << " = " << inf*RealScalar(1) << std::endl;
     49       first = false;
     50     }
     51   }
     52 
     53 
     54   Index rows = m.rows();
     55   Index cols = m.cols();
     56 
     57   // get a non-zero random factor
     58   Scalar factor = internal::random<Scalar>();
     59   while(numext::abs2(factor)<RealScalar(1e-4))
     60     factor = internal::random<Scalar>();
     61   Scalar big = factor * ((std::numeric_limits<RealScalar>::max)() * RealScalar(1e-4));
     62 
     63   factor = internal::random<Scalar>();
     64   while(numext::abs2(factor)<RealScalar(1e-4))
     65     factor = internal::random<Scalar>();
     66   Scalar small = factor * ((std::numeric_limits<RealScalar>::min)() * RealScalar(1e4));
     67 
     68   MatrixType  vzero = MatrixType::Zero(rows, cols),
     69               vrand = MatrixType::Random(rows, cols),
     70               vbig(rows, cols),
     71               vsmall(rows,cols);
     72 
     73   vbig.fill(big);
     74   vsmall.fill(small);
     75 
     76   VERIFY_IS_MUCH_SMALLER_THAN(vzero.norm(), static_cast<RealScalar>(1));
     77   VERIFY_IS_APPROX(vrand.stableNorm(),      vrand.norm());
     78   VERIFY_IS_APPROX(vrand.blueNorm(),        vrand.norm());
     79   VERIFY_IS_APPROX(vrand.hypotNorm(),       vrand.norm());
     80 
     81   RealScalar size = static_cast<RealScalar>(m.size());
     82 
     83   // test numext::isfinite
     84   VERIFY(!(numext::isfinite)( std::numeric_limits<RealScalar>::infinity()));
     85   VERIFY(!(numext::isfinite)(sqrt(-abs(big))));
     86 
     87   // test overflow
     88   VERIFY((numext::isfinite)(sqrt(size)*abs(big)));
     89   VERIFY_IS_NOT_APPROX(sqrt(copy(vbig.squaredNorm())), abs(sqrt(size)*big)); // here the default norm must fail
     90   VERIFY_IS_APPROX(vbig.stableNorm(), sqrt(size)*abs(big));
     91   VERIFY_IS_APPROX(vbig.blueNorm(),   sqrt(size)*abs(big));
     92   VERIFY_IS_APPROX(vbig.hypotNorm(),  sqrt(size)*abs(big));
     93 
     94   // test underflow
     95   VERIFY((numext::isfinite)(sqrt(size)*abs(small)));
     96   VERIFY_IS_NOT_APPROX(sqrt(copy(vsmall.squaredNorm())),   abs(sqrt(size)*small)); // here the default norm must fail
     97   VERIFY_IS_APPROX(vsmall.stableNorm(), sqrt(size)*abs(small));
     98   VERIFY_IS_APPROX(vsmall.blueNorm(),   sqrt(size)*abs(small));
     99   VERIFY_IS_APPROX(vsmall.hypotNorm(),  sqrt(size)*abs(small));
    100 
    101   // Test compilation of cwise() version
    102   VERIFY_IS_APPROX(vrand.colwise().stableNorm(),      vrand.colwise().norm());
    103   VERIFY_IS_APPROX(vrand.colwise().blueNorm(),        vrand.colwise().norm());
    104   VERIFY_IS_APPROX(vrand.colwise().hypotNorm(),       vrand.colwise().norm());
    105   VERIFY_IS_APPROX(vrand.rowwise().stableNorm(),      vrand.rowwise().norm());
    106   VERIFY_IS_APPROX(vrand.rowwise().blueNorm(),        vrand.rowwise().norm());
    107   VERIFY_IS_APPROX(vrand.rowwise().hypotNorm(),       vrand.rowwise().norm());
    108 
    109   // test NaN, +inf, -inf
    110   MatrixType v;
    111   Index i = internal::random<Index>(0,rows-1);
    112   Index j = internal::random<Index>(0,cols-1);
    113 
    114   // NaN
    115   {
    116     v = vrand;
    117     v(i,j) = std::numeric_limits<RealScalar>::quiet_NaN();
    118     VERIFY(!(numext::isfinite)(v.squaredNorm()));   VERIFY((numext::isnan)(v.squaredNorm()));
    119     VERIFY(!(numext::isfinite)(v.norm()));          VERIFY((numext::isnan)(v.norm()));
    120     VERIFY(!(numext::isfinite)(v.stableNorm()));    VERIFY((numext::isnan)(v.stableNorm()));
    121     VERIFY(!(numext::isfinite)(v.blueNorm()));      VERIFY((numext::isnan)(v.blueNorm()));
    122     VERIFY(!(numext::isfinite)(v.hypotNorm()));     VERIFY((numext::isnan)(v.hypotNorm()));
    123   }
    124 
    125   // +inf
    126   {
    127     v = vrand;
    128     v(i,j) = std::numeric_limits<RealScalar>::infinity();
    129     VERIFY(!(numext::isfinite)(v.squaredNorm()));   VERIFY(isPlusInf(v.squaredNorm()));
    130     VERIFY(!(numext::isfinite)(v.norm()));          VERIFY(isPlusInf(v.norm()));
    131     VERIFY(!(numext::isfinite)(v.stableNorm()));
    132     if(complex_real_product_ok){
    133       VERIFY(isPlusInf(v.stableNorm()));
    134     }
    135     VERIFY(!(numext::isfinite)(v.blueNorm()));      VERIFY(isPlusInf(v.blueNorm()));
    136     VERIFY(!(numext::isfinite)(v.hypotNorm()));     VERIFY(isPlusInf(v.hypotNorm()));
    137   }
    138 
    139   // -inf
    140   {
    141     v = vrand;
    142     v(i,j) = -std::numeric_limits<RealScalar>::infinity();
    143     VERIFY(!(numext::isfinite)(v.squaredNorm()));   VERIFY(isPlusInf(v.squaredNorm()));
    144     VERIFY(!(numext::isfinite)(v.norm()));          VERIFY(isPlusInf(v.norm()));
    145     VERIFY(!(numext::isfinite)(v.stableNorm()));
    146     if(complex_real_product_ok) {
    147       VERIFY(isPlusInf(v.stableNorm()));
    148     }
    149     VERIFY(!(numext::isfinite)(v.blueNorm()));      VERIFY(isPlusInf(v.blueNorm()));
    150     VERIFY(!(numext::isfinite)(v.hypotNorm()));     VERIFY(isPlusInf(v.hypotNorm()));
    151   }
    152 
    153   // mix
    154   {
    155     Index i2 = internal::random<Index>(0,rows-1);
    156     Index j2 = internal::random<Index>(0,cols-1);
    157     v = vrand;
    158     v(i,j) = -std::numeric_limits<RealScalar>::infinity();
    159     v(i2,j2) = std::numeric_limits<RealScalar>::quiet_NaN();
    160     VERIFY(!(numext::isfinite)(v.squaredNorm()));   VERIFY((numext::isnan)(v.squaredNorm()));
    161     VERIFY(!(numext::isfinite)(v.norm()));          VERIFY((numext::isnan)(v.norm()));
    162     VERIFY(!(numext::isfinite)(v.stableNorm()));    VERIFY((numext::isnan)(v.stableNorm()));
    163     VERIFY(!(numext::isfinite)(v.blueNorm()));      VERIFY((numext::isnan)(v.blueNorm()));
    164     VERIFY(!(numext::isfinite)(v.hypotNorm()));     VERIFY((numext::isnan)(v.hypotNorm()));
    165   }
    166 
    167   // stableNormalize[d]
    168   {
    169     VERIFY_IS_APPROX(vrand.stableNormalized(), vrand.normalized());
    170     MatrixType vcopy(vrand);
    171     vcopy.stableNormalize();
    172     VERIFY_IS_APPROX(vcopy, vrand.normalized());
    173     VERIFY_IS_APPROX((vrand.stableNormalized()).norm(), RealScalar(1));
    174     VERIFY_IS_APPROX(vcopy.norm(), RealScalar(1));
    175     VERIFY_IS_APPROX((vbig.stableNormalized()).norm(), RealScalar(1));
    176     VERIFY_IS_APPROX((vsmall.stableNormalized()).norm(), RealScalar(1));
    177     RealScalar big_scaling = ((std::numeric_limits<RealScalar>::max)() * RealScalar(1e-4));
    178     VERIFY_IS_APPROX(vbig/big_scaling, (vbig.stableNorm() * vbig.stableNormalized()).eval()/big_scaling);
    179     VERIFY_IS_APPROX(vsmall, vsmall.stableNorm() * vsmall.stableNormalized());
    180   }
    181 }
    182 
    183 void test_stable_norm()
    184 {
    185   for(int i = 0; i < g_repeat; i++) {
    186     CALL_SUBTEST_1( stable_norm(Matrix<float, 1, 1>()) );
    187     CALL_SUBTEST_2( stable_norm(Vector4d()) );
    188     CALL_SUBTEST_3( stable_norm(VectorXd(internal::random<int>(10,2000))) );
    189     CALL_SUBTEST_4( stable_norm(VectorXf(internal::random<int>(10,2000))) );
    190     CALL_SUBTEST_5( stable_norm(VectorXcd(internal::random<int>(10,2000))) );
    191   }
    192 }
    193