Re: How to reuse functions
ERRATA CORRIGE: in place of x_s replace with x_n. Sorry
Re: How to reuse functions
On Friday, 1 May 2015 at 11:03:19 UTC, anonymous wrote:
If x_n is a constant (enum), you can use that to create a
function instead of a delegate:
void main() {
enum real x_n = 1;
real x_m = -1;
real function(real) s_n = z = F1(z, x_n);
auto J = jac(s_n, x_m);
}
If x_n is not constant, then the only way I see to make this
work, is to use a module variable:
real x_n;
void main() {
x_n = 1;
real x_m = -1;
real function(real) s_n = z = F1(z, x_n);
auto J = jac(s_n, x_m);
}
On Friday, 1 May 2015 at 06:48:46 UTC, John Colvin wrote:
A combination of std.functional.reverseArgs and
std.functional.partial might help. It's unfortunately we don't
have a version that can set an arbitrary argument, only the
first one; It would be an easy improvement to make.
Thank you both. I understood what you have shown to me.
About the chain 'reverseArg'+'partial' I reached to use it
partially, only the partial part; so it worked with exception of
reverseArg. I made several attempt to make it working but without
succes.
About the scope/declaration suggestion they worked, fine. I've
also made a change declaring x_s as static and worked as well
(without change of scope and without use of enum).
Unfortunatly I tried to exted the code by introducing array of
functions F1-[F1, F2, ...] and I saw such solution cannot apply.
That why because of built functions passed (as example) to lambda
function they do not store information. And I went back to
delegates that store the necessary data to create the correct
function. I've seen some method to pass from delegates to
function, but onestly I found a to complex approach and much more
a workaround that a good programming.
Going back to my study of D I will find the right way of thinking
to approch such problems (I imagine now the trick could be using
templates... I will see).
Thanks again. I've learned many things by looking at you solution.
Re: How to reuse functions
On Friday, 1 May 2015 at 03:34:53 UTC, Luigi wrote:
Hi everybody.
I am tring to use a function where its parameter is another
function, and at the same time are both already made - they
cannot be modified - and the second one has to be conditioned
before to be passed as argument.
Let's say I have these function and I cannot modify:
-jac(+d) that works on function and return real
real jac(real function(real) fun, real x) {return d(fun, x);}
real d(real function(real) fun, real x) {return fun(x);}
-F1 that works on two reals and return real
real F1(real a, real b) {return a + b;}
So I need a way to condition F1 fixing b and then pass it to
jac as argument.
To do that I've created a delegate 'simp' conditionig F1:
real delegate(real) simp(real function(real, real) f, real x) {
real _simp(real z) {
return f(z, x);
}
return _simp;
}
(here 'simp' fixes b at x).
My main is:
void main() {
real x_n = 1;
real x_m = -1;
real delegate(real) s_n = simp(F1, x_n);
//auto J = jac(s_n, x_m); //Error: function app.jac (real
function(real) fun, real x) is not callable using argument
types (real delegate(real), real)
}
the code fails because jac expect as argument a function but I
found only a delegate to obtain a simplified function without
any touch at already made functions jac, d and F1.
There is a clean way to make it possible? I mean: without to
touch (neither rewrite) jac, d and F1, obtain simplied F1 to
pass to jac.
Thaks in advance to anyone could help me.
Luigi
A combination of std.functional.reverseArgs and
std.functional.partial might help. It's unfortunately we don't
have a version that can set an arbitrary argument, only the first
one; It would be an easy improvement to make.
Re: How to reuse functions
On Friday, 1 May 2015 at 03:34:53 UTC, Luigi wrote:
Hi everybody.
I am tring to use a function where its parameter is another
function, and at the same time are both already made - they
cannot be modified - and the second one has to be conditioned
before to be passed as argument.
Let's say I have these function and I cannot modify:
-jac(+d) that works on function and return real
real jac(real function(real) fun, real x) {return d(fun, x);}
real d(real function(real) fun, real x) {return fun(x);}
-F1 that works on two reals and return real
real F1(real a, real b) {return a + b;}
So I need a way to condition F1 fixing b and then pass it to
jac as argument.
To do that I've created a delegate 'simp' conditionig F1:
real delegate(real) simp(real function(real, real) f, real x) {
real _simp(real z) {
return f(z, x);
}
return _simp;
}
(here 'simp' fixes b at x).
My main is:
void main() {
real x_n = 1;
real x_m = -1;
real delegate(real) s_n = simp(F1, x_n);
//auto J = jac(s_n, x_m); //Error: function app.jac (real
function(real) fun, real x) is not callable using argument
types (real delegate(real), real)
}
the code fails because jac expect as argument a function but I
found only a delegate to obtain a simplified function without
any touch at already made functions jac, d and F1.
There is a clean way to make it possible? I mean: without to
touch (neither rewrite) jac, d and F1, obtain simplied F1 to
pass to jac.
If x_n is a constant (enum), you can use that to create a
function instead of a delegate:
void main() {
enum real x_n = 1;
real x_m = -1;
real function(real) s_n = z = F1(z, x_n);
auto J = jac(s_n, x_m);
}
If x_n is not constant, then the only way I see to make this
work, is to use a module variable:
real x_n;
void main() {
x_n = 1;
real x_m = -1;
real function(real) s_n = z = F1(z, x_n);
auto J = jac(s_n, x_m);
}
How to reuse functions
Hi everybody.
I am tring to use a function where its parameter is another
function, and at the same time are both already made - they
cannot be modified - and the second one has to be conditioned
before to be passed as argument.
Let's say I have these function and I cannot modify:
-jac(+d) that works on function and return real
real jac(real function(real) fun, real x) {return d(fun, x);}
real d(real function(real) fun, real x) {return fun(x);}
-F1 that works on two reals and return real
real F1(real a, real b) {return a + b;}
So I need a way to condition F1 fixing b and then pass it to jac
as argument.
To do that I've created a delegate 'simp' conditionig F1:
real delegate(real) simp(real function(real, real) f, real x) {
real _simp(real z) {
return f(z, x);
}
return _simp;
}
(here 'simp' fixes b at x).
My main is:
void main() {
real x_n = 1;
real x_m = -1;
real delegate(real) s_n = simp(F1, x_n);
//auto J = jac(s_n, x_m); //Error: function app.jac (real
function(real) fun, real x) is not callable using argument types
(real delegate(real), real)
}
the code fails because jac expect as argument a function but I
found only a delegate to obtain a simplified function without any
touch at already made functions jac, d and F1.
There is a clean way to make it possible? I mean: without to
touch (neither rewrite) jac, d and F1, obtain simplied F1 to pass
to jac.
Thaks in advance to anyone could help me.
Luigi
