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Strange output for Vector...

vv 14132 Maple 2017
vector print
December 11 2017
0 4

Here are two inocent Vectors.

> 

V1 := Vector[row]([`+`, 1, 2]);

_rtable[18446744074366295326]

 (1)
> 

V2 := Vector[row]([1, `+`, 2]);

_rtable[18446744074366288110]

 (2)
> 

lprint(V1);

Vector[row](3, {1 = `+`, 2 = 1, 3 = 2}, datatype = anything, storage = rectangular, order = Fortran_order, shape = [])

  

 

The questions:

 

1.  Try to guess the Maple's answer for:

 

> 

V1, V2;

 

2. Try to explain.

 


Download v1v2.mw

A simple evalf/Int crashes Maple...

vv 14132 Maple 2017
December 06 2017
0 8 
evalf(Int(x*(1-2*x^(3/10))^(10./3),x=0..1));  # Crashes Maple

Note that:

int(x*(1-2*x^(3/10))^(10./3),x=0..1);
int(x*(1-2*x^(3/10))^(10/3),x=0..1);
are OK.

(Windows 7, Maple 2017.3, 64 bit)

evalf[d] and Digits...

vv 14132 Maple
digits evalf
November 14 2017
0 0

A fact that seems to be not documented. Probably it should be obvious.

 

Digits := d0
evalf[d](expr);

 

The toplevel float sub-expressions in expr  are computed with Digits=d0 but in procedures Digits is set to d.
Notice that the actual float parameters of the toplevel procedures are evalf-ed with Digits=d0.

 

> 

restart;
> 

g:=proc() convert(1/3., string) end:
h:=proc() 1/3. end:
> 

Digits:=3;
evalf[10]([
  1/3. = h(),
  convert(1/3.,string) = g(),  
  fsolve(3*x=1) = add([1/3]),
  fsolve(x/3=1/9.) # 1/9. being at top level is evalf-ed with Digits=3
])

3

  

[.333 = .3333333333, ".333" = ".3333333333", .3333333333 = .3333333333, .3330000000]

 (1)
> 

 

> 

k:=proc(x) convert(x,string) end:
> 

kernelopts(floatPi);

true

 (2)
> 

4.+Pi;

7.14

 (3)
> 

evalf(k(1/3.+Pi));
# floatPi seems to be ignored inside actual parameters

".333+Pi"

 (4)
> 

evalf(k(4+evalf(Pi)));

"7.14"

 (5)
> 

evalf(k(4+Pi));
# 4 not being float (or "infected" by a float) is not evalf-ed

"4+Pi"

 (6)
> 

 

> 

### (this is documented)
> 

`evalf/h` := proc() 7.777 end:
> 

evalf(h(1/3));

.333

 (7)
> 

evalf('h'(1/3));

7.777

 (8)
> 

 

 

Download digits.mw

(edited)

Typesetting again...

vv 14132 Maple 2017
typesetting unames
November 02 2017
2 1 
restart;
unames();  # first call ok
unames();  # second call


Error, invalid input: Typeset:-Kernel expects an equation for keyword parameter numericformatting

Error, unexpected result from Typesetting

 

RootOf, index=real...

vv 14132 Maple
root rootof
October 24 2017
1 4

RootOf has the option index=real[i]  for the i-th real root:

evalf([seq(RootOf(x*(x^2-1)*(x^2-4)+1/100, x, index=real[i]), i=1..5)]);
     [-2.000416306, -0.9983310082, -0.002500019532, 1.001664362, 1.999582971]

This option does not seem to be documented. Why? Or, is it?

 

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