Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Hi

How can i get y value from a x value to show in a graph plot?. Like i can with the point probe, but i would like to mark it with a line.

Something like this (this is from a solution that isn't mine):

Where i am supposed to find y values to specific time values..

I rewrite my code with Grid library using local vCPU of amazon 

discover no license of distributed HPC when setup command show need go to acresso.com

can Grid still be used and function with local 96 number of vCPU?

then when I test code, I can not pkill mserver in ps -aux in LInux 

can the performance really improved ? Because I suppose 3 to 5 minutes mserver will end and disappear from ps -aux but grid node of mserver still running

originally I can run 100 batches every day., but I have to monitor decrease of memory in order to determine whether can kill mserver for next batch 

I expect run 400 batches per day. But Can not kill mserver when using grid

In my code I had using time limit(30, ...) 

when using Grid seq of function , can lprint work normally to get results into text ?

i notice Grid up to 57, do I need to recalculate and revise code to fit 96 vCPU for grid number 96?

Hello;I want to solve the following system.the result is not what I need.

with(linalg):

f1:=b*R + b*S - d*S - bcd*I1*S - bcd*I2*S - (e*g*S)/K - (g*I1*S)/K - ( g*I2*S)/K - (g*R*S)/K - (g*S^2)/K=0;

f2:=-d*e - (e^2*g)/K - (e*g*I1)/K - (e*g*I2)/K - (e*g*R)/K + bcd*I1*S +  bcd*I2*S - (e*g*S)/K - e*scd1=0;

f3:=-d*I1 - (e*g*I1)/K - (g*I1^2)/K - (g*I1*I2)/K - (g*I1*R)/K - ( g*I1*S)/K + e*scd1 - e*f*scd1 - I1*scd2=0;

f4:=-acd*I2 - d*I2 - (e*g*I2)/K - (g*I1*I2)/K - (g*I2^2)/K - ( g*I2*R)/K - (g*I2*S)/K + e*f*scd1=0;

f5:=-d*R - (e*g*R)/K - (g*I1*R)/K - (g*I2*R)/K - (g*R^2)/K - (g*R*S)/K +  I1*scd2=0;

solve({f1,f2,f3,f4,f5},{S,e,I1,I2,R});

What Maple function answers the following:

Produce (a minimal set of) sets that generate, by union, every intersection of sets given.

Examples:
F({1, 2, 3}, {1, 4, 5}, {2, 3, 4});

{}, {1}, {4}, {5}, {2, 3};


F({1, 2, 3, 6}, {1, 4, 5, 6}, {2, 3, 4, 6});
{1}, {4}, {5}, {6}, {2, 3};


Correction:
Produce (a minimal set of) disjoint sets that generate, by union, every intersection of sets given.

Intersection and union here are n-ary operators and every combination of sets is considered for intersection.

I have attached a maplework please check it. I want to solution graph by using RK 4th order with shooting technique or RK Fehlberg method. help.mw

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/help.mw .
 

Download help.mw

 

Sketch the 3d graph of solid bounded inside a sphere of x²+y²+z²=4z and below a cone z=√(x²+y²) on xy-plane.

Any one has smart way to help verify this Maple solution to this ODE? I can't figure it out

restart;
ode:=diff(y(x),x)-y(x) = x*y(x)^(1/2):
ic:= y(0)=4:
maple_sol:=dsolve([ode,ic],'implicit'):
the_diff_1:=odetest( (lhs-rhs)(maple_sol)=0,[ode,ic]);


maple_sol:=dsolve([ode,ic],'explicit'):
the_diff_2:=odetest( (lhs-rhs)(maple_sol)=0,[ode,ic]);

Tried few simplifications but not everything. I am assuming Maple solution is correct.

Maple 2021.1

Hello there, 

While I was trying to calculate the complex (i.e., P and Q) power equations, I got this question. 

Thus, I wonder if I can have a chance to ask the question here:

a. When the voltage and current are defined as functions, taking the t (time) as a input variable, I was not able to get the proper outcome from the operation. Those attempts are labeled as '#1' and '#2' in the attached worksheet. 

b. When the voltage and current are defined as simple complex expression, I was able to see what I wanted. The expression is named as 'ideal' in the attached worksheet. 

c. Therefore, my question is to see if there is a way to make the operaion using the functions in the same way as done by the simple expressions. 

d. Any insight would be appreciated. 

Thank you. 

Q20210617.mw

Dear Fellows, greetings

I am solving a system of equations under some assumptions and those assupmtions are a must to impose. However maple fails to apply those while solving the equations. For example solution 4 gives b=c as a solution but in assumtion it is clrealy mentioned that b<>c. Kindly guide me what mistake am I making in the code.

System_problem.mw

Background

This 'quirk' of Maple behaviour cropped up when I was considering solutions for the question posted here

https://www.mapleprimes.com/questions/232433-Extract-From-Record

where the OP had "poorly structured" data which meant it was a bit "awkward" to access required fields. A number of more-or-less satisfactory solution were proposed, and the OP seems happy

 

The Issue

One possible way to solve the original problem would be to restructure the data as a DataFrame. The "natural" way to do this would be to use numeric row indexes.. Note that these row indexes are not contiguous, and are in no particular order. However using this approach means that accessing fields from the dataframe is not consistent.

Sometimes the supplied row label is interpreted as a 'label', sometimes it is interpreted as the "row number". It appears that the latter interpretation is preferentially used

I can't make up my mind whether to call this a "bug" or not, but I can see the inconsistent interpretation resulting in chaos.

Before submitting an SCR I'd like to know if anyone else sees this as a bug

Consider the code

  restart;
  prettyprint=1:
#
# data
#
  S := [`206` = Record(mu = 508.001018040,  sigma = 125.002863204708),
          `4` = Record(mu = 1008.001018040, sigma = 167.707232430134),
          `2` = Record(mu = 1208.001018040, sigma = 141.512246146314),
          `5` = Record(mu = 808.001018040,  sigma = 117.156800098735)
       ]:
#
# Construct the above as a dataframe - note row labels are numbers!
#
  DF:= DataFrame( Matrix([seq( [rhs(j):-mu, rhs(j):-sigma], j in S)]),
                  rows= [seq( parse( lhs(j) ), j in S)],
                  columns=[mu, sigma]
              );
  DF[206, mu];
  DF[2, mu];  ## Errr No!
  DF[5, sigma];
               [           mu             sigma      ]
               [                                     ]
               [206  508.001018040   125.002863204708]
               [                                     ]
         DF := [ 4   1008.001018040  167.707232430134]
               [                                     ]
               [ 2   1208.001018040  141.512246146314]
               [                                     ]
               [ 5   808.001018040   117.156800098735]

                         508.001018040

                         1008.001018040

                        117.156800098735

Note that DF[2, mu] outputs the entry from the second row - not the one from the row labelled with the number 2

I imagina a similar issue would occur with numeric column indexes, although I haven't tried this
     

 

 

Hi

I have a list of records :

S := [`206` = Record(mu = 508.001018040, sigma = 125.002863204708), `4` = Record(mu = 1008.001018040, sigma = 167.707232430134), `2` = Record(mu = 1208.001018040, sigma = 141.512246146314), `5` = Record(mu = 808.001018040, sigma = 117.156800098735)]

How can I extract from S the mu and sd corresponding to a number.

eg input 2 get 1208.001018040,141.512246146314

like this:  rhs(S[3]):-mu, rhs(S[3]):-sigma, (I know from inpection 2 occurs in the 3rd slot but assume i don't know where it occurs). I tried using Search...
 

Suppose we have an unknown parametric function like g(x). We do not know the exact form but we know that g(x) is increasing and concave. Also, we define h(x) = g(x)*f(x) where we know the exact form of f(x) like f(x)=2x+5. Here, I want to investigate if the function h(x) is concave or not. How is it possible to do this?

 

Thanks

In this worksheet the solve command almost immediately gives up and DirectSearch[SolveEquations] is erratic.

For some triangle/inellipse points of tangency the latter provides a nonsense answer and for others it produces an almost correct solution.

Is there a set of conditions which determine the possibility of an inellipse within a triangle?

Inellipse.mw

A responder will have to establish a connection to the DirectSearch package.

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