Hi,<br><br>
<div class="gmail_quote">On Mon, Jan 31, 2011 at 5:15 PM, <span dir="ltr"><<a href="mailto:DParker@chromalloy.com">DParker@chromalloy.com</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote"><font size="2" face="sans-serif">I have several functions like the example below that I would like to make compatible with array inputs. The problem is the conditional statements give a <i>ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()</i>. I can use numpy.vectorize, but if possible I'd prefer to rewrite the function. Does anyone have any advice the best way to modify the code to accept array inputs? Thanks in advance for any assistance.</font></blockquote>
<div> </div>
<div>If I understod your question correctly, then air_gamma could be coded as:</div>
<div>def air_gamma_0(t, far=0.0): <br> """ <br> Specific heat ratio (gamma) of Air/JP8 <br> t - static temperature, Rankine <br> [far] - fuel air ratio [- defaults to 0.0 (dry air)] <br> air_gamma - specific heat ratio <br>
""" <br> if far< 0.: <br> return NAN <br> elif far < 0.005:<br> ag= air_gamma_1(t)<br> ag[np.logical_or(t< 379., t> 4731.)]= NAN<br> return ag<br> elif far< 0.069:<br>
ag= air_gamma_2(t, far)<br> ag[np.logical_or(t< 699., t> 4731.)]= NAN<br> return ag<br> else: <br> return NAN <br></div>
<div>Rest of the code is in the attachment.</div>
<div> </div>
<div> </div>
<div>My two cents,</div>
<div>eat</div>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote"><br><br><br><tt><font color="#000080" size="2">NAN = float('nan')</font></tt> <br><br><tt><font color="#000080" size="2">def air_gamma(t, far=0.0):</font></tt> <br>
<tt><font color="#000080" size="2"> """</font></tt> <br><tt><font color="#000080" size="2"> Specific heat ratio (gamma) of Air/JP8</font></tt> <br><tt><font color="#000080" size="2"> t - static temperature, Rankine</font></tt> <br>
<tt><font color="#000080" size="2"> [far] - fuel air ratio [- defaults to 0.0 (dry air)]</font></tt> <br><tt><font color="#000080" size="2"> air_gamma - specific heat ratio</font></tt> <br><tt><font color="#000080" size="2"> """</font></tt> <br>
<tt><font color="#000080" size="2"> if far < 0.:</font></tt> <br><tt><font color="#000080" size="2"> return NAN</font></tt> <br><tt><font color="#000080" size="2"> elif far < 0.005:</font></tt> <br><tt><font color="#000080" size="2"> if t < 379. or t > 4731.:</font></tt> <br>
<tt><font color="#000080" size="2"> return NAN</font></tt> <br><tt><font color="#000080" size="2"> else:</font></tt> <br><tt><font color="#000080" size="2"> air_gamma = -3.472487e-22 * t ** 6. + 6.218811e-18 * t ** 5. - 4.428098e-14 * t ** 4. + 1.569889e-10 * t ** 3. - 0.0000002753524 * t ** 2. + 0.0001684666 * t + 1.368652</font></tt> <br>
<tt><font color="#000080" size="2"> elif far < 0.069:</font></tt> <br><tt><font color="#000080" size="2"> if t < 699. or t > 4731.:</font></tt> <br><tt><font color="#000080" size="2"> return NAN</font></tt> <br>
<tt><font color="#000080" size="2"> else:</font></tt> <br><tt><font color="#000080" size="2"> a6 = 4.114808e-20 * far ** 3. - 1.644588e-20 * far ** 2. + 3.103507e-21 * far - 3.391308e-22</font></tt> <br>
<tt><font color="#000080" size="2"> a5 = -6.819015e-16 * far ** 3. + 2.773945e-16 * far ** 2. - 5.469399e-17 * far + 6.058125e-18</font></tt> <br><tt><font color="#000080" size="2"> a4 = 4.684637e-12 * far ** 3. - 1.887227e-12 * far ** 2. + 3.865306e-13 * far - 4.302534e-14</font></tt> <br>
<tt><font color="#000080" size="2"> a3 = -0.00000001700602 * far ** 3. + 0.000000006593809 * far ** 2. - 0.000000001392629 * far + 1.520583e-10</font></tt> <br><tt><font color="#000080" size="2"> a2 = 0.00003431136 * far ** 3. - 0.00001248285 * far ** 2. + 0.000002688007 * far - 0.0000002651616</font></tt> <br>
<tt><font color="#000080" size="2"> a1 = -0.03792449 * far ** 3. + 0.01261025 * far ** 2. - 0.002676877 * far + 0.0001580424</font></tt> <br><tt><font color="#000080" size="2"> a0 = 13.65379 * far ** 3. - 3.311225 * far ** 2. + 0.3573201 * far + 1.372714</font></tt> <br>
<tt><font color="#000080" size="2"> air_gamma = a6 * t ** 6. + a5 * t ** 5. + a4 * t ** 4. + a3 * t ** 3. + a2 * t ** 2. + a1 * t + a0</font></tt> <br><tt><font color="#000080" size="2"> elif far >= 0.069:</font></tt> <br>
<tt><font color="#000080" size="2"> return NAN</font></tt> <br><tt><font color="#000080" size="2"> else:</font></tt> <br><tt><font color="#000080" size="2"> return NAN</font></tt> <br><tt><font color="#000080" size="2"> return air_gamma</font></tt> <br>
<br><font size="2" face="Century Gothic">David Parker <br>Chromalloy - TDAG</font><br>_______________________________________________<br>NumPy-Discussion mailing list<br><a href="mailto:NumPy-Discussion@scipy.org">NumPy-Discussion@scipy.org</a><br>
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