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Mass position may be incorrect when amplitude is increased while sim is paused

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
javascript
Domain
frontend

Research direction

Start by reproducing the issue on the One Dimension Screen using the six-mass, paused-simulation steps and compare the behavior after stepping forward and pressing Initial Positions. Trace the simulation state update triggered by the sixth normal-mode slider; done means mass positions immediately reflect amplitude changes while paused, consistently matching the corrected initial positions.

Written by the indexing model from the issue text.

Description

priority:5-deferred type:bug

Test device
MacBook Air (m1 chip)

Operating System
12.0.1

Browser
Safari 15

Problem description
https://github.com/phetsims/qa/issues/733

Sometimes when the sim is paused and amplitude values are changed, the positions of the masses don't accurately reflect that change.

Steps to reproduce
This behavior is very inconsistent, but here are some steps that have worked for me:

  1. Open the One Dimension Screen
  2. Increase the number of masses to 6
  3. Press the pause button
  4. Move the slider for the 6th normal mode all the way up--the position of the masses barely changes. If you did not get this result, press the 'Reset All' button and follow the same steps again.
  5. Step forward a little and then press the 'Initial Positions' button. The initial positions are now correct for that amplitude value.

Visuals
initialposition

I do not see this behavior in the flash version
Screen Shot 2021-11-06 at 9 38 28 AM

Troubleshooting information: !!!!! DO NOT EDIT !!!!! Name: ‪Normal Modes‬ URL: https://phet-dev.colorado.edu/html/normal-modes/1.0.0-rc.1/phet/normal-modes_all_phet.html Version: 1.0.0-rc.1 2021-11-03 19:33:33 UTC Features missing: touch Flags: pixelRatioScaling User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.1 Safari/605.1.15 Language: en-US Window: 1427x698 Pixel Ratio: 2/1 WebGL: WebGL 1.0 GLSL: WebGL GLSL ES 1.0 (1.0) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 30 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32) Max viewport: 16384x16384 OES_texture_float: true Dependencies JSON: {}
Dominant language
JavaScript
Stars
0
Forks
2
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