el_first_kind; (int v, real z); -->
<p></p>
<p><code>real</code> <strong><code>modified_bessel_first_kind</code></strong><code>(int v, real z)</code><br>
Return the modified Bessel function of the first kind with order v
applied to z defined for all z and v. <span class="math display">\[
\mathrm{modified\_bessel\_first\_kind}(v,z) = I_v(z) \]</span> where <span class="math display">\[
{I_v}(z) = \left(\frac{1}{2}z\right)^v\sum_{k=0}^\infty
\frac{\left(\frac{1}{4}z^2\right)^k}{k!\Gamma(v+k+1)} \]</span></p>
