#### Topic: Explicit arguments

Great program. It's my playground for exploring math ideas. Everything works intuitively. The program rarely interferes with the creative process. Thanks especially for including gamma and zeta functions.

I'd like to take a product of a function over a range of primes. There doesn't appear to be a way to do this currently.

Some functions, like product() require arguments for start and end of a range of integers. It's not uncommon to need arguments which are irregular, like the divisors of n or roots of zeta. I'd like to be able to explicitly specify a list of arguments that is not simply a range of integers. Eg. product((x-1)/x, [2,3,5,7,11]).

To enhance this, it would be useful to have a function , say vector(f(x),a,b) that simply returns a list of values from evaluating f over the range a to b. Then product() and sum() could allow a single range argument like so: sum(1/x^2, vector(fact(x),1,7)) where sum takes each value from vector() as an argument.

A BASIC-like case() function and/or index() type function would also be nice for custom functions to return a specified member of a sequence. eg. nth_prime(x) := Return item x in [2,3,5,7,11,13,17].

#### Re: Explicit arguments

Oops, I found the ifseq function, so that should cover the last part reasonably well. I'll play with it and see.

#### Re: Explicit arguments

When Graph 4.4 is finished it will have some scripting possibilities, which should help support what you want.

As you have found, ifseq will help with some of the things currently. You may also be able to do some things with recursive functions.

#### Re: Explicit arguments

Good suggestion, Ivan. I want to expand a product of binomials into a sum of terms. Recursion is well suited to this task, but may be challenging without scripting.

Does the latest build include some scripting yet?
Any speculation on if 4.4 is getting close to finished?
Can the Beta and Latest Release be installed together?

Keep up the great work and excellent support.

#### Re: Explicit arguments

The beta version does contain some support for scripting, but not enough to be useful to you. And there is no documentation for it yet.

Unfortunately the development is going very slowly, so Graph 4.4 is not close to be released. My best guess is that it will take at least 6 months yet.

There should be no problem installing several version of Graph if you install them into different directories. However only the last installed version will have an icon in the start menu, but you can add another icon yourself.