Could someone suppress one of these two questions
232574-Error-In-Parametric-Plot
232573-Error-In-Parametric-Plot

and put tomleslie's answer and mine on the same threads?

TIA

Hi,

This question is related to the answer I gave to this question 232564-I-Need-To-Learn-What-Type-Of-Calculation

In a few words the OP (planetmknzm) wanted to know how a Maple's procedure (PlanePlot) was doing some calculus.
I proposed him to redirect the output of print('PlanePlot') to a mpl file, to open this latter, to insert a DEBUG() command and follow step by step what was going on.

If I execute the whole procedure (whose name is MyPlanePlot) I get this strange error
Error, (in MyPlanePlot) Colours is not a command in the Student package
Indeed PlanePlot contains instructions like this one

pl_Basis := plots['arrow']([[p, B[1]], [p, B[2]]], 'width' = pl_scale, 
      'colour' = Student:-Colours[2], op(basisoptions))

Searching for Colours in the help pages confirms what the error message says, but browsing the library with the assistant reveals that Student:-Colours does exist.

PlanePlot.mw

Do packages contain commands that are not accessible to users?
Why does PlanePlot work but its "clone" MyPlanePlot doesn't?
Last but not least, is there a way to fix this ?


Thanks in advance


PS : I discovered this issue as I was about to propose to planetmknzm another way to asked his previous question  232518-How-Can-We-Assign-The-Values-Of-Basis (just insert return B[1], B[2]: before the end of MyPlanePlot to get the vector basis)

Here is an example where (f@g)(..) cannot be written f(g(..)): When is @ necessary?

restart:
with(Statistics):
interface(displayprecision=4):
S := Sample(Uniform(-1, 1), 10):
((max-min)/Mean)(S);  # correctly evaluated

abs(Mean(S)); # correctly evaluated

((max-min)/abs(Mean))(S);  # unevaluated value: abs(Mean) appears as  |Statistics:-Mean| 

((max-min)/(abs@Mean))(S);  # correctly evaluated

Why does  1e-(Digits) return 1. and 1e-Digits generate an error?
 

1e-Digits;
Error, missing operator or `;`

1e(-Digits); 
                               1. 
type(Digits, posint)
                              true

Hi, 

I have  an expression made of a sum of different terms from which I want to extract all terms of a specific form.

A typical expression and the functions I want to extract is given in the attached file.

You will see in the example that the terms in the expression can be 

• a constant
• a continuous function of t
• a piecewise function like

  something*piecewise(a(t) < 0, A(t), a(t) < 1, B(t), ...)
  

• a piecewise function like

  something*piecewise(t < 0, A(t), t < 1, B(t), ...)

   

The functions I want to extract are only those of this latter form .

Thanks in advance

MyExpr.mw

PS: all the situations I have to manage contain expressions of the form of the prototype expression given in the attached file.
       Nothing more general than this.