fix for rendering of math characters in markdown of gradients tutorial

Author: andrewdelman

Tutorials_as_Jupyter_Notebooks/ECCO_v4_Gradient_calc_on_native_grid.ipynb

@@ -7,7 +7,7 @@
     "tags": []
    },
    "source": [
-    "*Contributors*: [Ian Fenty](https://github.com/ifenty), with minor edits by [Andrew Delman](https://github.com/andrewdelman).\n",
+    "*Contributors*: [Ian Fenty](https://github.com/ifenty), [Andrew Delman](https://github.com/andrewdelman).\n",
     "\n",
     "## Objectives\n",
     "\n",
@@ -93,7 +93,6 @@
     "\n",
     "from os.path import join,expanduser\n",
     "user_home_dir = expanduser('~')\n",
-    "# user_home_dir = '/Users/ifenty/'\n",
     "print(join(user_home_dir,'ECCOv4-py'))\n",
     "sys.path.append(join(user_home_dir,'ECCOv4-py'))\n",
     "import ecco_v4_py as ecco\n",
@@ -203,9 +202,9 @@
    "source": [
     "To calculate zonal and meridional gradients from ECCO fields on the lat-lon-cap grid we need to rotate vectors. In general it is easier and more accurate to first calculate our gradient vectors with respect to the orthogonal basis $M$ defined by the local $[x,y]$ coordinates of the model grid. The horizonal gradient of field, $f$ in the model basis is a vector comprised of the gradient in the local $x$ and $y$ directions in $M$.\n",
     "\n",
-    "$∇_M f =[\\partial_x f, \\partial_y f]_M$\n",
+    "$\\nabla_M f =[\\partial_x f, \\partial_y f]_M$\n",
     "\n",
-    "Once we know $∇_M f$, we can rotate the gradient vectors to the orthogonal basis $G$ of meridians and parallels. Rotation to $G$ from $M$ is accomplished via the change of basis matrix, $S_{M→G}$.\\\n",
+    "Once we know $\\nabla_M f$, we can rotate the gradient vectors to the orthogonal basis $G$ of meridians and parallels. Rotation to $G$ from $M$ is accomplished via the change of basis matrix, $S_{M→G}$.\\\n",
     "$S_{M→G} [\\partial_x f, \\partial_y f]_M  = [\\partial_x f, \\partial_y f]_G $\n",
     "\n",
     "After the change of basis, the vector $[\\partial_x f, \\partial_y f]_G$ contains the gradients of $f$ with respect to the zonal ($x:\\lambda$) and meridional ($y:\\phi$) directions, respectively. The subscripts $M$ and $G$ denote the basis of the vector.\n",
@@ -246,11 +245,11 @@
     "\n",
     "**Zonal gradient** of $f$:\n",
     "\n",
-    "[$\\partial_x f]_G       = [\\partial_x f]_M \\, cos(\\theta) - [\\partial_y f]_M \\, sin(\\theta)$\n",
+    "$[\\partial_x f]_G       = [\\partial_x f]_M \\, cos(\\theta) - [\\partial_y f]_M \\, sin(\\theta)$\n",
     "\n",
     "**Meridional gradient** of $f$:\n",
     "\n",
-    "[$\\partial_y f]_G       = [\\partial_x f]_M \\, sin(\\theta) + [\\partial_y f]_M \\, cos(\\theta)$\n",
+    "$[\\partial_y f]_G       = [\\partial_x f]_M \\, sin(\\theta) + [\\partial_y f]_M \\, cos(\\theta)$\n",
     "\n",
     "#### Plotting $sin(\\theta)$ and $cos(\\theta)$\n",
     "Plotting $SN$ and $CS$, shows the expected values for tiles 1 and 4 where $\\theta=0$: $sin(\\theta)=0$ and $cos(\\theta)=1$ and the expected values for tiles 8 and 11 where $\\theta=-\\pi/2$: $sin(\\theta)=-1$ and $cos(\\theta)=0$\n",
@@ -2313,12 +2312,12 @@
    "source": [
     "### Part 3: calculate vorticity from the flow field gradients\n",
     "\n",
-    "Let's wrap up this section by calcualting the relative vorticity: 𝝎=∇×𝐮\n",
+    "Let's wrap up this section by calcualting the relative vorticity: $\\bf{\\omega} = \\nabla\\times\\bf{u}$\n",
     "\n",
-    "***omega = dv/dx - du/dy***\n",
+    "$$\\omega = \\frac{\\partial{v}}{\\partial{x}} - \\frac{\\partial{u}}{\\partial{y}}$$\n",
     "\n",
-    "For the dv/dx term use the zonal gradient of meridional velocity,\n",
-    "`d_v_phi_dlambda` and for the du/dy term use the meridional gradient of zonal velocity,\n",
+    "For the $\\partial{v}/\\partial{x}$ term use the zonal gradient of meridional velocity,\n",
+    "`d_v_phi_dlambda` and for the $\\partial{u}/\\partial{y}$ term use the meridional gradient of zonal velocity,\n",
     "`d_u_lambda_dphi`.\n",
     "\n"
    ]

doc/conf.py

@@ -171,7 +171,6 @@
 
 # -- Options for LaTeX output ---------------------------------------------
 
-latex_engine = "xelatex"
 latex_elements = {
     # The paper size ('letterpaper' or 'a4paper').
     #