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aZira371 wants to merge 4 commits into from
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Enh/zero inertia tensor check #833

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8af308b
ENH: zero inertia check on rocket initialization (issue #826)
aZira371 Jun 13, 2025
a97c2b2
MNT: correction to input of inertia tensor into abs():
aZira371 Jun 20, 2025
cf494c4
Merge branch 'develop' into enh/zero-inertia-tensor-check
MateusStano Jul 4, 2025
fb94874
DEV: format and changelog
MateusStano Jul 4, 2025
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9 changes: 9 additions & 0 deletions rocketpy/rocket/rocket.py
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Original file line number Diff line number Diff line change
Expand Up @@ -293,6 +293,15 @@
self.I_12_without_motor = inertia[3]
self.I_13_without_motor = inertia[4]
self.I_23_without_motor = inertia[5]
inertia_matrix = Matrix([
[self.I_11_without_motor, self.I_12_without_motor, self.I_13_without_motor],
[self.I_12_without_motor, self.I_22_without_motor, self.I_23_without_motor],
[self.I_13_without_motor, self.I_23_without_motor, self.I_33_without_motor],
]) # Initial Inertia Tensor determinant singularity check
if abs(inertia_matrix) == 0:

Copilot AI Jun 22, 2025

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Using abs(inertia_matrix) to check for a singular matrix might not correctly compute the determinant; it is recommended to use the proper determinant method (e.g., inertia_matrix.det()) for an accurate singularity check.

Suggested change
if abs(inertia_matrix) == 0:
if inertia_matrix.det() == 0:

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"The rocket inertia tensor is singular (determinant is zero). "
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Comment on lines +295 to +317

@MateusStano MateusStano Jul 4, 2025

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I think having the dry inertia as zero should not stop the simulation, since someone might only have the inertias on the motor for some reason.

In any case, we need the determinant of the Rocket + Motor Inertia Matrix to be different from zero. Could you move this check so that it is done when a motor is added?

@aZira371 aZira371 Jul 4, 2025

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So you mean to say someone might want to simulate just a motor and check the trajectory?

Yes agreed I'll move it to when the motor is added.


# Define rocket geometrical parameters in SI units
self.center_of_mass_without_motor = center_of_mass_without_motor
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