equivalent to C pointer
Hi everybody,
I am new to python and I am discovering it.
I know C well,
and want to know if python knows how to manage Pointers
like pointer to function here is a C example how to write it in python
Intergration with trapeze method
When we write Trapeze ( at the compilation level) we don't know which
functions
Fonc to handle. Here for example we use sin and a user defined F1
The program is attached too
#include
#include
double F1 (double x){
return x*x;
}
double Trapeze(double Fonc(double ),
double left, double right, double step){
double X1, X0, Y0, Y1, Z = 0;
for(X0=left; X0 < right ; X0 = X0 + step) {
X1 = X0 + step;
Y1 = Fonc(X1);Y0 = Fonc(X0);
Z += (Y1 + Y0) * step * 0.5;
}
return Z;
}
int main(){
double y;
y=Trapeze(sin, -2.5, 3.2, 0.1);
printf("\n\tValue for sin is : \t %8.3lf ", y);
y=Trapeze(F1, 0, 3, 0.1);
printf("\n\tValue for F1 is : \t %8.3lf ", y);
return 0;
}
/**
Value for sin is : 0.197
Value for F1 is : 9.005
*/
thanks a lot
#include
#include
double F1 (double x){
return x*x;
}
double Trapeze(double Fonc(double ),
double left, double right, double step){
double X1, X0, Y0, Y1, Z = 0;
for(X0=left; X0 < right ; X0 = X0 + step) {
X1 = X0 + step;
Y1 = Fonc(X1);Y0 = Fonc(X0);
Z += (Y1 + Y0) * step * 0.5;
}
return Z;
}
int main(){
double y;
y=Trapeze(sin, -2.5, 3.2, 0.1);
printf("\n\tValue for sin is : \t %8.3lf ", y);
y=Trapeze(F1, 0, 3, 0.1);
printf("\n\tValue for F1 is : \t %8.3lf ", y);
return 0;
}
/**
Value for sin is : 0.197
Value for F1 is : 9.005
*/
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Re: equivalent to C pointer
Thanks for answer,
but with C we can compile the trapeze function and put it in librairy,
If we try to save the trapeze alone in package to import it later, I
think, I am not sure
it will be refused because F1 and sin are not define !!! this is the
power of the C pointers !!!
the link is dynamic
thanks
On Thu, Apr 18, 2013 at 6:17 PM, Karim wrote:
>
> Hello,
>
> There is no such notion in python.
> But the closest are iterators and generator functions.
>
> Cheers
> Karim
>
>
> On 18/04/2013 19:06, abdelkader belahcene wrote:
>
> Hi everybody,
>
> I am new to python and I am discovering it.
> I know C well,
> and want to know if python knows how to manage Pointers
> like pointer to function here is a C example how to write it in python
> Intergration with trapeze method
>
> When we write Trapeze ( at the compilation level) we don't know which
> functions
> Fonc to handle. Here for example we use sin and a user defined F1
> The program is attached too
>
> #include
> #include
>
> double F1 (double x){
> return x*x;
> }
> double Trapeze(double Fonc(double ),
> double left, double right, double step){
> double X1, X0, Y0, Y1, Z = 0;
> for(X0=left; X0 < right ; X0 = X0 + step) {
> X1 = X0 + step;
> Y1 = Fonc(X1);Y0 = Fonc(X0);
> Z += (Y1 + Y0) * step * 0.5;
> }
>return Z;
> }
> int main(){
> double y;
> y=Trapeze(sin, -2.5, 3.2, 0.1);
> printf("\n\tValue for sin is : \t %8.3lf ", y);
> y=Trapeze(F1, 0, 3, 0.1);
> printf("\n\tValue for F1 is : \t %8.3lf ", y);
> return 0;
> }
> /**
> Value for sin is : 0.197
> Value for F1 is : 9.005
> */
> thanks a lot
>
>
>
>
--
http://mail.python.org/mailman/listinfo/python-list
Re: equivalent to C pointer
Thanks a lot, I think this does the task
cheers
On Thu, Apr 18, 2013 at 7:14 PM, David Robinow wrote:
> On Thu, Apr 18, 2013 at 1:50 PM, abdelkader belahcene <
> abelahc...@gmail.com> wrote:
>
>> Thanks for answer,
>> but with C we can compile the trapeze function and put it in librairy,
>> If we try to save the trapeze alone in package to import it later, I
>> think, I am not sure
>> it will be refused because F1 and sin are not define !!! this is the
>> power of the C pointers !!!
>> the link is dynamic
>>
> You don't need C pointers. The design below is demonstrative, not ideal.
>
> # file MyFuncs.py
>
> def F1(x):
> return x*x
>
> def Trapeze(f, left, right, step):
> X0 = left
> Z = 0.0
> while (X0 < right):
> X1 = X0 + step
> Y1 = f(X1)
> Y0 = f(X0)
>
> Z += (Y1 + Y0) * step * 0.5
> X0 = X1
> return Z
>
>
>
> # file UseMyFuncs.py
> import math
> import MyFuncs
>
> def main():
> y = MyFuncs.Trapeze(math.sin, -2.5, 3.2, 0.1)
>
> print("Value for sin is:{0} ".format(y))
> y = MyFuncs.Trapeze(MyFuncs.F1, 0, 3, 0.1)
>
> print("Value for F1 is {0} ".format(y))
>
> if __name__ == "__main__":
> main()
>
> ###
> #python3 UseMyFuncs.py
> ###
>
>
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