Files
Upsilon/poincare/src/randint.cpp
2020-11-04 15:58:41 +01:00

83 lines
3.2 KiB
C++

#include <poincare/randint.h>
#include <poincare/complex.h>
#include <poincare/infinity.h>
#include <poincare/integer.h>
#include <poincare/layout_helper.h>
#include <poincare/random.h>
#include <poincare/rational.h>
#include <poincare/undefined.h>
#include <poincare/serialization_helper.h>
#include <ion.h>
extern "C" {
#include <assert.h>
}
#include <cmath>
namespace Poincare {
constexpr Expression::FunctionHelper Randint::s_functionHelper;
int RandintNode::numberOfChildren() const { return Randint::s_functionHelper.numberOfChildren(); }
Layout RandintNode::createLayout(Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const {
return LayoutHelper::Prefix(Randint(this), floatDisplayMode, numberOfSignificantDigits, Randint::s_functionHelper.name());
}
int RandintNode::serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const {
return SerializationHelper::Prefix(this, buffer, bufferSize, floatDisplayMode, numberOfSignificantDigits, Randint::s_functionHelper.name());
}
template <typename T> Evaluation<T> RandintNode::templateApproximate(ApproximationContext approximationContext, bool * inputIsUndefined) const {
Evaluation<T> aInput = childAtIndex(0)->approximate(T(), approximationContext);
Evaluation<T> bInput = childAtIndex(1)->approximate(T(), approximationContext);
if (inputIsUndefined) {
*inputIsUndefined = aInput.isUndefined() || bInput.isUndefined();
}
T a = aInput.toScalar();
T b = bInput.toScalar();
/* randint is undefined if:
* - one of the bounds is NAN or INF
* - the last bound is lesser than the first one
* - one of the input cannot be represented by an integer
* (here we don't test a != std::round(a) because we want the inputs to
* hold all digits so to be representable as an int)
* - the range between bounds is too large to be covered by all double between
* 0 and 1 - we can't map the integers of the range with all representable
* double numbers from 0 to 1.
* */
if (std::isnan(a) || std::isnan(b) || std::isinf(a) || std::isinf(b)
|| a > b
|| a != (int)a || b != (int)b
|| (Expression::Epsilon<T>()*(b+(T)1.0-a) > (T)1.0)) {
return Complex<T>::RealUndefined();
}
T result = std::floor(Random::random<T>()*(b+(T)1.0-a)+a);
return Complex<T>::Builder(result);
}
Expression RandintNode::shallowReduce(ReductionContext reductionContext) {
return Randint(this).shallowReduce(reductionContext);
}
Expression Randint::shallowReduce(ExpressionNode::ReductionContext reductionContext) {
Expression e = Expression::defaultShallowReduce();
e = e.defaultHandleUnitsInChildren();
if (e.isUndefined()) {
return e;
}
bool inputIsUndefined = false;
double eval = static_cast<RandintNode *>(node())->templateApproximate<double>(ExpressionNode::ApproximationContext(reductionContext, true), &inputIsUndefined).toScalar();
if (inputIsUndefined) {
/* The input might be NAN because we are reducing a function's expression
* which depends on x. We thus do not want to replace too early with
* undefined. */
return *this;
}
Expression result = Number::DecimalNumber(eval);
replaceWithInPlace(result);
return result.shallowReduce(reductionContext);
}
}