From a97a41f6c03c60c0b628d2a9caceec8e182b6222 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Villemot?= <sebastien@dynare.org>
Date: Thu, 21 Jul 2022 17:22:08 +0200
Subject: [PATCH] Bugfix with temporary terms in block+bytecode
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There were actually two distinct bugs, leading to incorrect results in some
corner cases:
– in the “evaluate” mode of the bytecode MEX, the temporary terms of the
derivatives “evaluate” blocks were not evaluated at runtime; but these
temporary terms may be needed for residuals of subsequent blocks;
– when the bytecode MEX was only computing residuals of the model (and not 1st
order derivatives), the temporary terms of the derivatives were not evaluated
at runtime; but these temporary terms may be needed for residuals of subsequent
blocks.
---
src/ModelTree.hh | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/src/ModelTree.hh b/src/ModelTree.hh
index 7c0a5746..bcb4a6d8 100644
--- a/src/ModelTree.hh
+++ b/src/ModelTree.hh
@@ -1303,15 +1303,18 @@ ModelTree::writeBlockBytecodeHelper(BytecodeWriter &code_file, int block) const
code_file << FBINARY_{BinaryOpcode::minus} << FSTPR_{i - block_recursive};
}
}
- code_file << FENDEQU_{};
- /* If the block is not of type “evaluate backward/forward”, then we write
- the temporary terms for derivatives at this point, i.e. before the
- JMPIFEVAL, because they will be needed in both “simulate” and
- “evaluate” modes. */
- if (simulation_type != BlockSimulationType::evaluateBackward
- && simulation_type != BlockSimulationType::evaluateForward)
- write_eq_tt(blocks[block].size);
+ /* Write temporary terms for derivatives. This is done before FENDEQU,
+ because residuals of a subsequent block may depend on temporary terms for
+ the derivatives of the present block.
+
+ Also note that in the case of “evaluate” blocks, derivatives are not
+ computed in the “evaluate” mode; still their temporary terms must be
+ computed even in that mode, because for the same reason as above they may
+ be needed in subsequent blocks. */
+ write_eq_tt(blocks[block].size);
+
+ code_file << FENDEQU_{};
// Get the current code_file position and jump if evaluating
int pos_jmpifeval {code_file.getInstructionCounter()};
@@ -1411,13 +1414,6 @@ ModelTree::writeBlockBytecodeHelper(BytecodeWriter &code_file, int block) const
// Update jump offset for previous JMPIFEVAL
code_file.overwriteInstruction(pos_jmpifeval, FJMPIFEVAL_{pos_jmp-pos_jmpifeval});
- /* If the block is of type “evaluate backward/forward”, then write the
- temporary terms for derivatives at this point, because they have not
- been written before the JMPIFEVAL. */
- if (simulation_type == BlockSimulationType::evaluateBackward
- || simulation_type == BlockSimulationType::evaluateForward)
- write_eq_tt(blocks[block].size);
-
// Write the derivatives for the “evaluate” mode
for (const auto &[indices, d] : blocks_derivatives[block])
{
--
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