Carl Love

Carl Love

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12 years, 336 days
Himself
Wayland, Massachusetts, United States
My name was formerly Carl Devore.

MaplePrimes Activity


These are replies submitted by Carl Love

@wolfman29 It is a bug, because it is supposed to accept functions that way in 2D input, with a popup asking whether you want to define a function or make a remember table entry.

@brian bovril I corrected the code in the Answer, changing 2 to 3. Note that ilog10(x) is one less than the number of digits in x, so the precision is now 2 digits more than are in x. Since the next fibonacci could have at most one more digit than x, this gives one guard digit to guard against round-off errors in the intermediate calculation.

Regarding the Font: So, were you able to get through the menu sequence? If so, did it seem to change anything at all?

@brian bovril I corrected the code in the Answer, changing 2 to 3. Note that ilog10(x) is one less than the number of digits in x, so the precision is now 2 digits more than are in x. Since the next fibonacci could have at most one more digit than x, this gives one guard digit to guard against round-off errors in the intermediate calculation.

Regarding the Font: So, were you able to get through the menu sequence? If so, did it seem to change anything at all?

@J4James Where did you get the "exact" solution? It seems wrong. You can check that it doesn't satisfy the original equations like this:

F1test:= unapply(Exact, eta):
eval(eq1, F1= F1test):
plot(lhs(%), eta= 0..n);

It should be identically 0, modulo some rounding errors. Note that I am not comparing Exact against the computed numeric solution; I am comparing against the original differential equation.

Please ask any further questions in a separate thread. You're lucky that I saw your Reply, because it is difficult to find Replies to old Answers.

 

@J4James Where did you get the "exact" solution? It seems wrong. You can check that it doesn't satisfy the original equations like this:

F1test:= unapply(Exact, eta):
eval(eq1, F1= F1test):
plot(lhs(%), eta= 0..n);

It should be identically 0, modulo some rounding errors. Note that I am not comparing Exact against the computed numeric solution; I am comparing against the original differential equation.

Please ask any further questions in a separate thread. You're lucky that I saw your Reply, because it is difficult to find Replies to old Answers.

 

I think that the Asker wants single-precison hardware floats, which can be accessed with datatype= float[4].

I think that the Asker wants single-precison hardware floats, which can be accessed with datatype= float[4].

There is no file attached to your post.

To change the default input to the way I have it, go through the following menu sequence: Tools => Options => Display => Input Display => Maple Notation => Apply Globally.

There must be a difference in the floating-point evaluation in Maple 15 or a different processor that you may be using. I cannot reproduce your errors. The evalf is necessary to handle cases where the fibonacci has more than Digits digits. Without it, the ceil and round will return unevaluated for > > 10^Digits.

Please try testing with one more digit of precision: Change evalf[2+ilog10(x)] to evalf[3+ilog10(x)].

To change the default input to the way I have it, go through the following menu sequence: Tools => Options => Display => Input Display => Maple Notation => Apply Globally.

There must be a difference in the floating-point evaluation in Maple 15 or a different processor that you may be using. I cannot reproduce your errors. The evalf is necessary to handle cases where the fibonacci has more than Digits digits. Without it, the ceil and round will return unevaluated for > > 10^Digits.

Please try testing with one more digit of precision: Change evalf[2+ilog10(x)] to evalf[3+ilog10(x)].

@brian bovril 

The command for that is

map(`>`, {a,b,c,d}, 0);

Note that the quotes are back quotes, not aposthropes. What the above means is

  1. `>` is an operator that takes two arguments,
  2. the first argument is taken iteratively from {a,b,c,d},
  3. the second argument is always 0.

Another command that does the same thing is

{seq(x>0, x= {a,b,c,d})};

@brian bovril 

The command for that is

map(`>`, {a,b,c,d}, 0);

Note that the quotes are back quotes, not aposthropes. What the above means is

  1. `>` is an operator that takes two arguments,
  2. the first argument is taken iteratively from {a,b,c,d},
  3. the second argument is always 0.

Another command that does the same thing is

{seq(x>0, x= {a,b,c,d})};

@ecterrab I am using Maple 17.01, Standard GUI, 64-bit, Windows 8. The given macro command fixes the problem for me.

@Kitonum This last piece of code is very impressive.

@Kitonum This last piece of code is very impressive.

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