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Fix Issue 833 #835

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merged 4 commits into from
Oct 7, 2022
Merged

Fix Issue 833 #835

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e884ca4
Correct 1F1[-n, -n, x]
jzmaddock Oct 4, 2022
ad15484
Pass policy in forwarding call to gamma_q.
jzmaddock Oct 5, 2022
7f54e6f
Fix bug in 1F1 recurrence relations when one term goes to zero.
jzmaddock Oct 6, 2022
db0c40a
Merge branch 'develop' into issue833
jzmaddock Oct 6, 2022
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2 changes: 2 additions & 0 deletions include/boost/math/special_functions/detail/hypergeometric_1F1_recurrence.hpp
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Expand Up @@ -330,6 +330,8 @@
first = 1;
ak -= 1;
second = 1 - z / b;
if (fabs(second) < 0.5)
second = (b - z) / b; // cancellation avoidance
}
else
{
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7 changes: 6 additions & 1 deletion include/boost/math/special_functions/hypergeometric_1F1.hpp
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Expand Up @@ -317,7 +317,12 @@ namespace boost { namespace math { namespace detail {

// other checks:
if (a == -1)
return 1 - (z / b);
{
T r = 1 - (z / b);
if (fabs(r) < 0.5)
r = (b - z) / b;
return r;
}

const T b_minus_a = b - a;

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2 changes: 1 addition & 1 deletion include/boost/math/tools/recurrence.hpp
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Expand Up @@ -209,7 +209,7 @@ namespace boost {
{
tie(a, b, c) = get_coefs(-static_cast<int>(k));

if ((log_scaling) &&
if ((log_scaling) && (second != 0) &&
( (fabs(tools::max_value<T>() * (a / b) / 2048) < fabs(second))
|| (fabs(tools::max_value<T>() * (a / c) / 2048) < fabs(first))
|| (fabs(tools::min_value<T>() * (a / b) * 2048) > fabs(second))
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36 changes: 35 additions & 1 deletion test/test_1F1.hpp
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Expand Up @@ -162,7 +162,7 @@ void test_spots5(T, const char* type_name)
template <class T>
void test_spots6(T, const char* type_name)
{
static const std::array<std::array<T, 4>, 153> hypergeometric_1F1_bugs = { {
static const std::array<std::array<T, 4>, 183> hypergeometric_1F1_bugs = { {
{ { static_cast<double>(17955.561660766602), static_cast<double>(9.6968994205831605e-09), static_cast<double>(-82.406154185533524), SC_(6.98056008378736714088730927132364938220428678e-11) }},
{ { static_cast<double>(17955.561660766602), static_cast<double>(-9.6968994205831605e-09), static_cast<double>(-82.406154185533524), SC_(-6.98055306629610746072607353939306734740549551e-11) }},
{ { static_cast<double>(-17955.561660766602), static_cast<double>(-9.6968994205831605e-09), static_cast<double>(82.406154185533524), SC_(-42897094853118832762870100.8669248353530950866) }} ,
Expand Down Expand Up @@ -356,6 +356,40 @@ void test_spots6(T, const char* type_name)
{ { -28, -28, 23.5, SC_(1.3636649055777180973706533952884087e10) } },
{ { -29, -29, 23.5, SC_(1.4288921731123489919940015692546766e10) } },
{ { -30, -30, 23.5, SC_(1.4799868660144765261156243055282531e10) } },
//
// Special cases for 1F1[-n, n, n], recurrence relations explode for these
// so we need to take special care, see:
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Was there supposed to be something after "see:"?

//
{ {-1, 1, 1, 0} },
{ { -2, 2, 2, SC_(-0.33333333333333333333333333333333333) } },
{ { -3, 3, 3, SC_(-0.20000000000000000000000000000000000) } },
{ { -4, 4, 4, SC_(-0.028571428571428571428571428571428571) } },
{ { -5, 5, 5, SC_(0.034391534391534391534391534391534392) } },
{ { -6, 6, 6, SC_(0.025974025974025974025974025974025974) } },
{ { -7, 7, 7, SC_(0.0055458430458430458430458430458430458) } },
{ { -8, 8, 8, SC_(-0.0034844168177501510834844168177501511) } },
{ { -9, 9, 9, SC_(-0.0032789269553975436328377504848093083) } },
{ { -10, 10, 10, SC_(-0.00090655818209997776561244053504115424) } },
{ { -11, 11, 11, SC_(0.00032882634672802494317065057641990169) } },
{ { -12, 12, 12, SC_(0.00040482026290537337976908770901425171) } },
{ { -13, 13, 13, SC_(0.00013693942490239899363731963133279724) } },
{ { -14, 14, 14, SC_(-0.000027114521961598289657552462032956946) } },
{ { -15, 15, 15, SC_(-0.000048914265972106416241933622562193726) } },
{ { -16, 16, 16, SC_(-0.000019682683030825726780784406799223748) } },
{ { -17, 17, 17, SC_(1.5839922420851958320021705281180291e-6) } },
{ { -18, 18, 18, SC_(5.7780970016822066007807309411610877e-6) } },
{ { -19, 19, 19, SC_(2.7286504926687308865490707120168935e-6) } },
{ { -20, 20, 20, SC_(3.0777012229800824850242341264747930e-8) } },
{ { -21, 21, 21, SC_(-6.6559501148858176979489331026765573e-7) } },
{ { -22, 22, 22, SC_(-3.6755193543651782101726439542497979e-7) } },
{ { -23, 23, 23, SC_(-3.2293485126433594872416984294551283e-8) } },
{ { -24, 24, 24, SC_(7.4437711540037326179190703001784924e-8) } },
{ { -25, 25, 25, SC_(4.8312843928329924033336815590280938e-8) } },
{ { -26, 26, 26, SC_(7.5047977770302588786691782818325643e-9) } },
{ { -27, 27, 27, SC_(-8.0223979804469656047588860706683494e-9) } },
{ { -28, 28, 28, SC_(-6.2125286411657869483728921158018766e-9) } },
{ { -29, 29, 29, SC_(-1.3521578972057573423569167878458172e-9) } },
{{ -30, 30, 30, SC_(8.2238878884841599031462003461115991e-10) } },
} };
static const std::array<std::array<T, 4>, 2> hypergeometric_1F1_big_bugs = { {
#if DBL_MAX_EXP == LDBL_MAX_EXP
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