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[poincare] 0*inf should be undef, not 0

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This commit is contained in:
Léa Saviot
2018-09-13 17:48:42 +02:00
parent 1c2079dcf5
commit 5c2ab75ea1
1 changed files with 20 additions and 17 deletions
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37
poincare/src/multiplication.cpp
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@@ -265,21 +265,12 @@ Expression Multiplication::privateShallowReduce(Context & context, Preferences::
* which also are multiplications themselves. */
mergeMultiplicationChildrenInPlace();
/* Step 2: If any of the child is zero, the multiplication result is zero */
for (int i = 0; i < numberOfChildren(); i++) {
const Expression c = childAtIndex(i);
if (c.type() == ExpressionNode::Type::Rational && static_cast<const Rational &>(c).isZero()) {
replaceWithInPlace(c);
return c;
}
}
// Step 3: Sort the children
// Step 2: Sort the children
sortChildrenInPlace(ExpressionNode::SimplificationOrder, canBeInterrupted);
#if MATRIX_EXACT_REDUCING
#if 0 // OLD CODE
/* Step 3bis: get rid of matrix */
/* Step 2bis: get rid of matrix */
int n = 1;
int m = 1;
/* All children have been simplified so if any child contains a matrix, it
@@ -353,7 +344,7 @@ Expression Multiplication::privateShallowReduce(Context & context, Preferences::
#endif
#endif
/* Step 4: Gather like terms. For example, turn pi^2*pi^3 into pi^5. Thanks to
/* Step 3: Gather like terms. For example, turn pi^2*pi^3 into pi^5. Thanks to
* the simplification order, such terms are guaranteed to be next to each
* other. */
int i = 0;
@@ -380,7 +371,7 @@ Expression Multiplication::privateShallowReduce(Context & context, Preferences::
i++;
}
/* Step 5: We look for terms of form sin(x)^p*cos(x)^q with p, q rational of
/* Step 4: We look for terms of form sin(x)^p*cos(x)^q with p, q rational of
*opposite signs. We replace them by either:
* - tan(x)^p*cos(x)^(p+q) if |p|<|q|
* - tan(x)^(-q)*sin(x)^(p+q) otherwise */
@@ -404,7 +395,7 @@ Expression Multiplication::privateShallowReduce(Context & context, Preferences::
* shallowReduce */
sortChildrenInPlace(ExpressionNode::SimplificationOrder, canBeInterrupted);
/* Step 6: We remove rational children that appeared in the middle of sorted
/* Step 5: We remove rational children that appeared in the middle of sorted
* children. It's important to do this after having factorized because
* factorization can lead to new ones. Indeed:
* pi^(-1)*pi-> 1
@@ -435,11 +426,23 @@ Expression Multiplication::privateShallowReduce(Context & context, Preferences::
}
i++;
}
if (childAtIndex(0).type() == ExpressionNode::Type::Rational && childAtIndex(0).convert<Rational>().isOne() && numberOfChildren() > 1) {
removeChildAtIndexInPlace(0);
/* Step 5: If the first child is zero, the multiplication result is zero. We
* do this after merging the rational children, because the merge takes care
* of turning 0*inf into undef.
* If the first child is 1, we remove it if there are other children. */
{
const Expression c = childAtIndex(0);
if (c.type() == ExpressionNode::Type::Rational && static_cast<const Rational &>(c).isZero()) {
replaceWithInPlace(c);
return c;
}
if (c.type() == ExpressionNode::Type::Rational && static_cast<const Rational &>(c).isOne() && numberOfChildren() > 1) {
removeChildAtIndexInPlace(0);
}
}
/* Step 7: Expand multiplication over addition children if any. For example,
/* Step 6: Expand multiplication over addition children if any. For example,
* turn (a+b)*c into a*c + b*c. We do not want to do this step right now if
* the parent is a multiplication to avoid missing factorization such as
* (x+y)^(-1)*((a+b)*(x+y)).