topic Re: acceleration of system of ODE in PTC Mathcad
https://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418896#M164040
<HTML><HEAD></HEAD><BODY><P>... the list shows that I replied twice, not true , only 1.</P><P>Click right on Odesove and see the two options:</P><P>fixed, adapt ... Odesolve is a numerical solver, it displays</P><P>the "lsplined numerical solution", therefore it it not an</P><P>export, i.e: it resides on the work sheet , solely.</P><P></P><P>In the attached example, we solve a 2nd order DE for</P><P>3 parameters [m = 1, 25, 50]. The two text box interpolate,</P><P>interpolate at ponit or collects a range of interpolated values.</P><P>You CAN'T naturally change the built-in lspline Odesolve.</P><P>On some project, you might want to see the other pspline,</P><P>cspline... There was complaints about that rigidity, here</P><P>it is solved: simple elegant . The trick is to pass the internal</P><P>vector of solution to a transit local loop. At this point, it is</P><P>easy to decide which spline you want to use. The other trick</P><P>is to pair the internal vector of solutions with a discretized</P><P>vector of the ranged integration variable .</P><P></P><P>In "S" we collect the 3 parameters [m = 1, 25, 50] solutions</P><P>You can collect as many as you want. The text box collects</P><P>the solutions you want as governed by the global definition 'j'.</P><P></P><P>Below, I have added the first and 2nd derivatives plots.</P><P></P><P>Whether it does help or not in your project, can't tell because</P><P>you had no work sheet attached, readable by Mathcad 11.</P><P></P><P>My point here is more than about solving the given DE, it is</P><P>essentially about using the advanced technique of using a</P><P>"local transit exploder". This same techique was posted</P><P>a day or two ago for collecting functions f(x,y) from a main</P><P>vector of user functions for plotting.</P><P></P><P>jmG</P><P></P><P>I hate that compobox, it should show a dummy vertical</P><P>dotted line about where my reply will appear once posted.</P><P>All that result from the indenting, a useless invention.</P><P>This PTC community is about dead on the number of Mathcad</P><P>discusions. Hopefully and for a while the webmaster</P><P>reads for all the comments and suggestions that now</P><P>have no place where to put them.</P></BODY></HTML>Sun, 04 Jul 2010 16:55:35 GMTjeanGiraud2010-07-04T16:55:35Zacceleration of system of ODE
https://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418894#M164038
After a long search story at last I ask here my question.I had a system of 2nd order constant coeff. linear ODE which describes a reduced geartrain with a motor function.I used rkadapt to solve the system and obtaiened displacement and velocity plots. My next step was to draw accelerationThu, 03 May 2018 19:28:56 GMThttps://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418894#M164038caksu2018-05-03T19:28:56ZRe: acceleration of system of ODE
https://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418895#M164039
<HTML><HEAD></HEAD><BODY><P>rk is not as robust as Odesolve and there is about no point using rk</P><P>because it's one the Odesolve integrator. With Odesolve, you get</P><P>all the functions : the primitive, first and 2nd derivative, which 2nd</P><P>derivative is the acceleration, What you get from Odesolve plots</P><P>are not exportable functions, only display functions.</P><P>For an export, you must approximate the data set from the</P><P>Odesolve solutions.</P><P></P><P>jmG </P></BODY></HTML>Sun, 04 Jul 2010 04:48:30 GMThttps://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418895#M164039jeanGiraud2010-07-04T04:48:30ZRe: acceleration of system of ODE
https://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418896#M164040
<HTML><HEAD></HEAD><BODY><P>... the list shows that I replied twice, not true , only 1.</P><P>Click right on Odesove and see the two options:</P><P>fixed, adapt ... Odesolve is a numerical solver, it displays</P><P>the "lsplined numerical solution", therefore it it not an</P><P>export, i.e: it resides on the work sheet , solely.</P><P></P><P>In the attached example, we solve a 2nd order DE for</P><P>3 parameters [m = 1, 25, 50]. The two text box interpolate,</P><P>interpolate at ponit or collects a range of interpolated values.</P><P>You CAN'T naturally change the built-in lspline Odesolve.</P><P>On some project, you might want to see the other pspline,</P><P>cspline... There was complaints about that rigidity, here</P><P>it is solved: simple elegant . The trick is to pass the internal</P><P>vector of solution to a transit local loop. At this point, it is</P><P>easy to decide which spline you want to use. The other trick</P><P>is to pair the internal vector of solutions with a discretized</P><P>vector of the ranged integration variable .</P><P></P><P>In "S" we collect the 3 parameters [m = 1, 25, 50] solutions</P><P>You can collect as many as you want. The text box collects</P><P>the solutions you want as governed by the global definition 'j'.</P><P></P><P>Below, I have added the first and 2nd derivatives plots.</P><P></P><P>Whether it does help or not in your project, can't tell because</P><P>you had no work sheet attached, readable by Mathcad 11.</P><P></P><P>My point here is more than about solving the given DE, it is</P><P>essentially about using the advanced technique of using a</P><P>"local transit exploder". This same techique was posted</P><P>a day or two ago for collecting functions f(x,y) from a main</P><P>vector of user functions for plotting.</P><P></P><P>jmG</P><P></P><P>I hate that compobox, it should show a dummy vertical</P><P>dotted line about where my reply will appear once posted.</P><P>All that result from the indenting, a useless invention.</P><P>This PTC community is about dead on the number of Mathcad</P><P>discusions. Hopefully and for a while the webmaster</P><P>reads for all the comments and suggestions that now</P><P>have no place where to put them.</P></BODY></HTML>Sun, 04 Jul 2010 16:55:35 GMThttps://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418896#M164040jeanGiraud2010-07-04T16:55:35ZRe: acceleration of system of ODE
https://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418897#M164041
<HTML><HEAD></HEAD><BODY><P> With a second order system you should have a function (defining the system) giving acceleration as a function of the other variables. Just evaluate that function.</P></BODY></HTML>Mon, 05 Jul 2010 01:05:48 GMThttps://community.ptc.com/t5/PTC-Mathcad/acceleration-of-system-of-ODE/m-p/418897#M164041TomGutman2010-07-05T01:05:48Z