Update app.py

app.py

@@ -5,9 +5,9 @@ import plotly.graph_objects as go
 
 # Configure Streamlit for Hugging Face Spaces
 st.set_page_config(
-   page_title="Cubic Root Analysis",
-   layout="wide",
-   initial_sidebar_state="collapsed"
+    page_title="Cubic Root Analysis",
+    layout="wide",
+    initial_sidebar_state="collapsed"
 )
 
 #############################
@@ -25,8 +25,8 @@ d_sym = 1
 
 # Symbolic expression for the standard cubic discriminant
 Delta_expr = (
-   ( (b_sym*c_sym)/(6*a_sym**2) - (b_sym**3)/(27*a_sym**3) - d_sym/(2*a_sym) )**2
-   + ( c_sym/(3*a_sym) - (b_sym**2)/(9*a_sym**2) )**3
+    ( (b_sym*c_sym)/(6*a_sym**2) - (b_sym**3)/(27*a_sym**3) - d_sym/(2*a_sym) )**2
+    + ( c_sym/(3*a_sym) - (b_sym**2)/(9*a_sym**2) )**3
 )
 
 # Turn that into a fast numeric function:
@@ -34,219 +34,225 @@ discriminant_func = sp.lambdify((z_sym, beta_sym, z_a_sym, y_sym), Delta_expr, "
 
 @st.cache_data
 def find_z_at_discriminant_zero(z_a, y, beta, z_min, z_max, steps=20000):
-   """
-   Numerically scan z in [z_min, z_max] looking for sign changes of
-   Delta(z) = 0. Returns all roots found via bisection.
-   """
-   z_grid = np.linspace(z_min, z_max, steps)
-   disc_vals = discriminant_func(z_grid, beta, z_a, y)
-   
-   roots_found = []
-   
-   # Scan for sign changes
-   for i in range(len(z_grid) - 1):
-       f1, f2 = disc_vals[i], disc_vals[i+1]
-       if np.isnan(f1) or np.isnan(f2):
-           continue
-       
-       if f1 == 0.0:
-           roots_found.append(z_grid[i])
-       elif f2 == 0.0:
-           roots_found.append(z_grid[i+1])
-       elif f1*f2 < 0:
-           zl = z_grid[i]
-           zr = z_grid[i+1]
-           for _ in range(50):
-               mid = 0.5*(zl + zr)
-               fm = discriminant_func(mid, beta, z_a, y)
-               if fm == 0:
-                   zl = zr = mid
-                   break
-               if np.sign(fm) == np.sign(f1):
-                   zl = mid
-                   f1 = fm
-               else:
-                   zr = mid
-                   f2 = fm
-           root_approx = 0.5*(zl + zr)
-           roots_found.append(root_approx)
-   
-   return np.array(roots_found)
+    """
+    Numerically scan z in [z_min, z_max] looking for sign changes of
+    Delta(z) = 0. Returns all roots found via bisection.
+    """
+    z_grid = np.linspace(z_min, z_max, steps)
+    disc_vals = discriminant_func(z_grid, beta, z_a, y)
+    
+    roots_found = []
+    
+    # Scan for sign changes
+    for i in range(len(z_grid) - 1):
+        f1, f2 = disc_vals[i], disc_vals[i+1]
+        if np.isnan(f1) or np.isnan(f2):
+            continue
+        
+        if f1 == 0.0:
+            roots_found.append(z_grid[i])
+        elif f2 == 0.0:
+            roots_found.append(z_grid[i+1])
+        elif f1*f2 < 0:
+            zl = z_grid[i]
+            zr = z_grid[i+1]
+            for _ in range(50):
+                mid = 0.5*(zl + zr)
+                fm = discriminant_func(mid, beta, z_a, y)
+                if fm == 0:
+                    zl = zr = mid
+                    break
+                if np.sign(fm) == np.sign(f1):
+                    zl = mid
+                    f1 = fm
+                else:
+                    zr = mid
+                    f2 = fm
+            root_approx = 0.5*(zl + zr)
+            roots_found.append(root_approx)
+    
+    return np.array(roots_found)
 
 @st.cache_data
 def sweep_beta_and_find_z_bounds(z_a, y, z_min, z_max, beta_steps=51):
-   """
-   For each beta, find both the largest and smallest z where discriminant=0.
-   Returns (betas, z_min_values, z_max_values).
-   """
-   betas = np.linspace(0, 1, beta_steps)
-   z_min_values = []
-   z_max_values = []
-   
-   for b in betas:
-       roots = find_z_at_discriminant_zero(z_a, y, b, z_min, z_max)
-       if len(roots) == 0:
-           z_min_values.append(np.nan)
-           z_max_values.append(np.nan)
-       else:
-           z_min_values.append(np.min(roots))
-           z_max_values.append(np.max(roots))
-   
-   return betas, np.array(z_min_values), np.array(z_max_values)
+    """
+    For each beta, find both the largest and smallest z where discriminant=0.
+    Returns (betas, z_min_values, z_max_values).
+    """
+    betas = np.linspace(0, 1, beta_steps)
+    z_min_values = []
+    z_max_values = []
+    
+    for b in betas:
+        roots = find_z_at_discriminant_zero(z_a, y, b, z_min, z_max)
+        if len(roots) == 0:
+            z_min_values.append(np.nan)
+            z_max_values.append(np.nan)
+        else:
+            z_min_values.append(np.min(roots))
+            z_max_values.append(np.max(roots))
+    
+    return betas, np.array(z_min_values), np.array(z_max_values)
 
 @st.cache_data
 def compute_low_y_curve(betas, z_a, y):
-   """
-   Compute the additional curve with proper handling of divide by zero cases
-   """
-   with np.errstate(invalid='ignore', divide='ignore'):
-       sqrt_term = y * betas * (z_a - 1)
-       sqrt_term = np.where(sqrt_term < 0, np.nan, np.sqrt(sqrt_term))
-       
-       term = (-1 + sqrt_term)/z_a
-       numerator = (y - 2)*term + y * betas * ((z_a - 1)/z_a) - 1/z_a - 1
-       denominator = term**2 + term
-       
-       mask = (denominator == 0) | np.isnan(denominator) | np.isnan(numerator)
-       result = np.zeros_like(denominator)
-       result[~mask] = numerator[~mask] / denominator[~mask]
-       result[mask] = np.nan
-       
-       return result
+    """
+    Compute the additional curve with proper handling of divide by zero cases
+    """
+    betas = np.array(betas)
+    with np.errstate(invalid='ignore', divide='ignore'):
+        sqrt_term = y * betas * (z_a - 1)
+        sqrt_term = np.where(sqrt_term < 0, np.nan, np.sqrt(sqrt_term))
+        
+        term = (-1 + sqrt_term)/z_a
+        numerator = (y - 2)*term + y * betas * ((z_a - 1)/z_a) - 1/z_a - 1
+        denominator = term**2 + term
+        
+        # Handle division by zero and invalid values
+        result = np.zeros_like(betas)
+        mask = (denominator != 0) & ~np.isnan(denominator) & ~np.isnan(numerator)
+        result[mask] = numerator[mask] / denominator[mask]
+        result[~mask] = np.nan
+        
+        return result
 
 @st.cache_data
 def compute_high_y_curve(betas, z_a, y):
-   """
-   Compute the expression: ((4y + 12)(4 - a) + 16y*β*(a - 1))/(3(4 - a))
-   """
-   a = z_a  # for clarity in the formula
-   with np.errstate(invalid='ignore', divide='ignore'):
-       numerator = (4*y + 12)*(4 - a) + 16*y*betas*(a - 1)
-       denominator = 3*(4 - a)
-       
-       # Handle division by zero
-       mask = (denominator == 0)
-       result = np.zeros_like(denominator, dtype=float)
-       result[~mask] = numerator[~mask] / denominator[~mask]
-       result[mask] = np.nan
-       
-       return result
+    """
+    Compute the expression: ((4y + 12)(4 - a) + 16y*β*(a - 1))/(3(4 - a))
+    """
+    a = z_a  # for clarity in the formula
+    betas = np.array(betas)
+    
+    with np.errstate(invalid='ignore', divide='ignore'):
+        numerator = (4*y + 12)*(4 - a) + 16*y*betas*(a - 1)
+        denominator = 3*(4 - a)
+        
+        result = np.zeros_like(betas)
+        mask = (denominator != 0)
+        result[mask] = numerator[mask] / denominator[mask]
+        result[~mask] = np.nan
+        
+        return result
 
 def generate_z_vs_beta_plot(z_a, y, z_min, z_max):
-   if z_a <= 0 or y <= 0 or z_min >= z_max:
-       st.error("Invalid input parameters.")
-       return None
-   
-   beta_steps = 101
-   
-   betas, z_mins, z_maxs = sweep_beta_and_find_z_bounds(z_a, y, z_min, z_max, beta_steps=beta_steps)
-   low_y_curve = compute_low_y_curve(betas, z_a, y)
-   high_y_curve = compute_high_y_curve(betas, z_a, y)
-   
-   fig = go.Figure()
-   
-   fig.add_trace(
-       go.Scatter(
-           x=betas,
-           y=z_maxs,
-           mode="markers+lines",
-           name="Upper z*(β)",
-           marker=dict(size=5, color='blue'),
-           line=dict(color='blue'),
-       )
-   )
-   
-   fig.add_trace(
-       go.Scatter(
-           x=betas,
-           y=z_mins,
-           mode="markers+lines",
-           name="Lower z*(β)",
-           marker=dict(size=5, color='lightblue'),
-           line=dict(color='lightblue'),
-       )
-   )
-   
-   fig.add_trace(
-       go.Scatter(
-           x=betas,
-           y=low_y_curve,
-           mode="markers+lines",
-           name="Low y Expression",
-           marker=dict(size=5, color='red'),
-           line=dict(color='red'),
-       )
-   )
-   
-   fig.add_trace(
-       go.Scatter(
-           x=betas,
-           y=high_y_curve,
-           mode="markers+lines",
-           name="High y Expression",
-           marker=dict(size=5, color='green'),
-           line=dict(color='green'),
-       )
-   )
-   
-   fig.update_layout(
-       title="Curves vs β: z*(β) boundaries and Asymptotic Expressions",
-       xaxis_title="β",
-       yaxis_title="Value",
-       hovermode="x unified",
-   )
-   return fig
+    if z_a <= 0 or y <= 0 or z_min >= z_max:
+        st.error("Invalid input parameters.")
+        return None
+    
+    beta_steps = 101
+    betas = np.linspace(0, 1, beta_steps)
+    
+    betas, z_mins, z_maxs = sweep_beta_and_find_z_bounds(z_a, y, z_min, z_max, beta_steps=beta_steps)
+    low_y_curve = compute_low_y_curve(betas, z_a, y)
+    high_y_curve = compute_high_y_curve(betas, z_a, y)
+    
+    fig = go.Figure()
+    
+    # Upper and lower z*(β) boundaries
+    fig.add_trace(
+        go.Scatter(
+            x=betas,
+            y=z_maxs,
+            mode="markers+lines",
+            name="Upper z*(β)",
+            marker=dict(size=5, color='blue'),
+            line=dict(color='blue'),
+        )
+    )
+    
+    fig.add_trace(
+        go.Scatter(
+            x=betas,
+            y=z_mins,
+            mode="markers+lines",
+            name="Lower z*(β)",
+            marker=dict(size=5, color='lightblue'),
+            line=dict(color='lightblue'),
+        )
+    )
+    
+    # Asymptotic expressions
+    fig.add_trace(
+        go.Scatter(
+            x=betas,
+            y=low_y_curve,
+            mode="markers+lines",
+            name="Low y Expression",
+            marker=dict(size=5, color='red'),
+            line=dict(color='red'),
+        )
+    )
+    
+    fig.add_trace(
+        go.Scatter(
+            x=betas,
+            y=high_y_curve,
+            mode="markers+lines",
+            name="High y Expression",
+            marker=dict(size=5, color='green'),
+            line=dict(color='green'),
+        )
+    )
+    
+    fig.update_layout(
+        title="Curves vs β: z*(β) boundaries and Asymptotic Expressions",
+        xaxis_title="β",
+        yaxis_title="Value",
+        hovermode="x unified",
+    )
+    return fig
 
 @st.cache_data
 def compute_cubic_roots(z, beta, z_a, y):
-   """
-   Compute the roots of the cubic equation for given parameters.
-   Returns array of complex roots.
-   """
-   a = z * z_a
-   b = z * z_a + z + z_a - z_a*y  # Fixed coefficient b
-   c = z + z_a + 1 - y*(beta*z_a + 1 - beta)
-   d = 1
-   
-   coeffs = [a, b, c, d]
-   roots = np.roots(coeffs)
-   return roots
+    """
+    Compute the roots of the cubic equation for given parameters.
+    Returns array of complex roots.
+    """
+    a = z * z_a
+    b = z * z_a + z + z_a - z_a*y  # Fixed coefficient b
+    c = z + z_a + 1 - y*(beta*z_a + 1 - beta)
+    d = 1
+    
+    coeffs = [a, b, c, d]
+    roots = np.roots(coeffs)
+    return roots
 
 def generate_ims_vs_z_plot(beta, y, z_a, z_min, z_max):
-   if z_a <= 0 or y <= 0 or z_min >= z_max:
-       st.error("Invalid input parameters.")
-       return None
-   
-   z_points = np.linspace(z_min, z_max, 1000)
-   ims = []
-   
-   for z in z_points:
-       roots = compute_cubic_roots(z, beta, z_a, y)
-       roots = sorted(roots, key=lambda x: abs(x.imag))
-       ims.append([root.imag for root in roots])
-   
-   ims = np.array(ims)
-   
-   fig = go.Figure()
-   
-   for i in range(3):
-       fig.add_trace(
-           go.Scatter(
-               x=z_points,
-               y=ims[:,i],
-               mode="lines",
-               name=f"Im{{s{i+1}}}",
-               line=dict(width=2),
-           )
-       )
-   
-   fig.update_layout(
-       title=f"Im{{s}} vs. z (β={beta:.3f}, y={y:.3f}, z_a={z_a:.3f})",
-       xaxis_title="z",
-       yaxis_title="Im{s}",
-       hovermode="x unified",
-   )
-   return fig
+    if z_a <= 0 or y <= 0 or z_min >= z_max:
+        st.error("Invalid input parameters.")
+        return None
+    
+    z_points = np.linspace(z_min, z_max, 1000)
+    ims = []
+    
+    for z in z_points:
+        roots = compute_cubic_roots(z, beta, z_a, y)
+        roots = sorted(roots, key=lambda x: abs(x.imag))
+        ims.append([root.imag for root in roots])
+    
+    ims = np.array(ims)
+    
+    fig = go.Figure()
+    
+    for i in range(3):
+        fig.add_trace(
+            go.Scatter(
+                x=z_points,
+                y=ims[:,i],
+                mode="lines",
+                name=f"Im{{s{i+1}}}",
+                line=dict(width=2),
+            )
+        )
+    
+    fig.update_layout(
+        title=f"Im{{s}} vs. z (β={beta:.3f}, y={y:.3f}, z_a={z_a:.3f})",
+        xaxis_title="z",
+        yaxis_title="Im{s}",
+        hovermode="x unified",
+    )
+    return fig
 
 # Streamlit UI
 st.title("Cubic Root Analysis")
@@ -254,51 +260,51 @@ st.title("Cubic Root Analysis")
 tab1, tab2 = st.tabs(["z*(β) Curves", "Im{s} vs. z"])
 
 with tab1:
-   st.header("Find z Values where Cubic Roots Transition Between Real and Complex")
-   
-   col1, col2 = st.columns([1, 2])
-   
-   with col1:
-       z_a_1 = st.number_input("z_a", value=1.0, key="z_a_1")
-       y_1 = st.number_input("y", value=1.0, key="y_1")
-       z_min_1 = st.number_input("z_min", value=-10.0, key="z_min_1")
-       z_max_1 = st.number_input("z_max", value=10.0, key="z_max_1")
-       
-       if st.button("Compute z vs. β Curves"):
-           with col2:
-               fig = generate_z_vs_beta_plot(z_a_1, y_1, z_min_1, z_max_1)
-               if fig is not None:
-                   st.plotly_chart(fig, use_container_width=True)
-                   
-                   st.markdown("### Additional Expressions")
-                   st.markdown("""
-                   **Low y Expression (Red):**
-                   ```
-                   ((y - 2)*(-1 + sqrt(y*β*(a-1)))/a + y*β*((a-1)/a) - 1/a - 1) / 
-                   ((-1 + sqrt(y*β*(a-1)))/a)^2 + (-1 + sqrt(y*β*(a-1)))/a)
-                   ```
-                   
-                   **High y Expression (Green):**
-                   ```
-                   ((4y + 12)(4 - a) + 16y*β*(a - 1))/(3(4 - a))
-                   ```
-                   where a = z_a
-                   """)
+    st.header("Find z Values where Cubic Roots Transition Between Real and Complex")
+    
+    col1, col2 = st.columns([1, 2])
+    
+    with col1:
+        z_a_1 = st.number_input("z_a", value=1.0, key="z_a_1")
+        y_1 = st.number_input("y", value=1.0, key="y_1")
+        z_min_1 = st.number_input("z_min", value=-10.0, key="z_min_1")
+        z_max_1 = st.number_input("z_max", value=10.0, key="z_max_1")
+        
+        if st.button("Compute z vs. β Curves"):
+            with col2:
+                fig = generate_z_vs_beta_plot(z_a_1, y_1, z_min_1, z_max_1)
+                if fig is not None:
+                    st.plotly_chart(fig, use_container_width=True)
+                    
+                    st.markdown("### Additional Expressions")
+                    st.markdown("""
+                    **Low y Expression (Red):**
+                    ```
+                    ((y - 2)*(-1 + sqrt(y*β*(a-1)))/a + y*β*((a-1)/a) - 1/a - 1) / 
+                    ((-1 + sqrt(y*β*(a-1)))/a)^2 + (-1 + sqrt(y*β*(a-1)))/a)
+                    ```
+                    
+                    **High y Expression (Green):**
+                    ```
+                    ((4y + 12)(4 - a) + 16y*β*(a - 1))/(3(4 - a))
+                    ```
+                    where a = z_a
+                    """)
 
 with tab2:
-   st.header("Plot Imaginary Parts of Roots vs. z")
-   
-   col1, col2 = st.columns([1, 2])
-   
-   with col1:
-       beta = st.number_input("β", value=0.5, min_value=0.0, max_value=1.0)
-       y_2 = st.number_input("y", value=1.0, key="y_2")
-       z_a_2 = st.number_input("z_a", value=1.0, key="z_a_2")
-       z_min_2 = st.number_input("z_min", value=-10.0, key="z_min_2")
-       z_max_2 = st.number_input("z_max", value=10.0, key="z_max_2")
-       
-       if st.button("Compute Im{s} vs. z"):
-           with col2:
-               fig = generate_ims_vs_z_plot(beta, y_2, z_a_2, z_min_2, z_max_2)
-               if fig is not None:
-                   st.plotly_chart(fig, use_container_width=True)
+    st.header("Plot Imaginary Parts of Roots vs. z")
+    
+    col1, col2 = st.columns([1, 2])
+    
+    with col1:
+        beta = st.number_input("β", value=0.5, min_value=0.0, max_value=1.0)
+        y_2 = st.number_input("y", value=1.0, key="y_2")
+        z_a_2 = st.number_input("z_a", value=1.0, key="z_a_2")
+        z_min_2 = st.number_input("z_min", value=-10.0, key="z_min_2")
+        z_max_2 = st.number_input("z_max", value=10.0, key="z_max_2")
+        
+        if st.button("Compute Im{s} vs. z"):
+            with col2:
+                fig = generate_ims_vs_z_plot(beta, y_2, z_a_2, z_min_2, z_max_2)
+                if fig is not None:
+                    st.plotly_chart(fig, use_container_width=True)