<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yiv4444753403"><div id="yui_3_16_0_1_1422681420002_2228" style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px; background-color: rgb(255, 255, 255);"><div id="yui_3_16_0_1_1422681420002_2227" dir="ltr">Dear all,</div><div id="yui_3_16_0_1_1422681420002_2344" dir="ltr">I am a newer to GSASII, and I sent a letter to all of you last night. The problem I met was that a sigular matrix appeared when I chose to refine the texture parameters. Later, I tried to do it many times, and I found that I set chi=90 degree in texture item, which I thought it should be. I changed 90 to the value "0", and the problem solved. I was confused by two types of Eulerian angle, one for sample (Tree:PWDR--sample parameters), and another for the phase (Tree:Phase--texture). I remember that there are only one type of Eulerian angle in GSAS, and the default value of omega, chi, and phi for Bragg Brentano geometry is respectively, 0, 90, 0. However, what is the default value for these different types of Eulerian angle in GSASII? </div><div id="yui_3_16_0_1_1422681420002_2638" dir="ltr">Another problem is that the restraint does not work when more than one phases are rifined. For example, there are three phases, anatase, pyrite and microcline. The default phase in GSASII is anatase which can be set up for application of restraint when I chose the "restraint" item, however I plan to apply the restraints for microcline. The "restraint" dialogue box became a grey background when I change the phase from anatase to microcline in the menu "Edit--Select", and a hint appeared that "NameError: free variable 'Status" referenced before assignment in enclosing scope" in the console window. In order to solve this problem, I deleted other two phases, and only kept microline in GSASII. Then, the function of "restraint" worked. Is there any methods or suggestions to solve this problem?</div><div id="yui_3_16_0_1_1422681420002_2958" dir="ltr"> </div><div id="yui_3_16_0_1_1422681420002_2957" dir="ltr">Thanks, Daxu</div></div></div></div></body></html>